[BUG] No captcha displayed. Only sometimes displayed, but rarely

My config:

version: "1.1.14"
# Available serializers:
# LEGACY_AMPERSAND - "&c&lExample &c&9Text".
# LEGACY_SECTION - "§c§lExample §c§9Text".
# MINIMESSAGE - "<bold><red>Example</red> <blue>Text</blue></bold>". (https://webui.adventure.kyori.net/)
# GSON - "[{"text":"Example","bold":true,"color":"red"},{"text":" ","bold":true},{"text":"Text","bold":true,"color":"blue"}]". (https://minecraft.tools/en/json_text.php/)
# GSON_COLOR_DOWNSAMPLING - Same as GSON, but uses downsampling.
serializer: LEGACY_AMPERSAND
prefix: "&9Бот-фильтр &8>>&r"

# Don't use \n, use {NL} for new line, and {PRFX} for prefix.
main:
  # Check if player's Minecraft client sends the network packet with the settings.
  check-client-settings: true
  # Check if player's Minecraft client has a brand.
  check-client-brand: true
  # If player's Minecraft client brand (e.g. fabric or forge) is set here, then this player will be kicked.
  blocked-client-brands:
    - "brand1"
    - "brand2"
  # Time in milliseconds, how frequently will the cache list with verified players be reset. Before that time, verified players can join the server without passing antibot checks.
  purge-cache-millis: 3600000
  # Max attempts, which a player has to solve the captcha.
  captcha-attempts: 3
  # Duration of Falling Check in Minecraft ticks (1 tick = 0.05 second, 20 ticks = 1 second).
  falling-check-ticks: 100
  # Maximum time to check the player in milliseconds. If the player stays on the filter limbo for longer than this time, then the check will fail.
  time-out: 20000
  # Same, but for Geyser users.
  geyser-time-out: 45000
  # The timeout for Netty. Max ping while being on the filter limbo. Used to remove useless buffers from RAM.
  max-ping: 3500
  # Change the parameters below only if you know what they mean.
  non-valid-position-xz-attempts: 10
  non-valid-position-y-attempts: 10
  max-valid-position-difference: 0.01
  # Parameter for developers and contributors.
  falling-check-debug: false
  # Should captcha be displayed in the left hand. May cause problems with entering captcha for users with 4:3 monitors. Version: 1.9+
  captcha-left-hand: false
  # Available states: ONLY_POSITION, ONLY_CAPTCHA, CAPTCHA_POSITION, CAPTCHA_ON_POSITION_FAILED
  # Meaning: 
  # ONLY_POSITION -> Only falling check (Player will be spawned in the void, server will check player's coordinates, speed, acceleration).
  # ONLY_CAPTCHA -> Only captcha (Map items with a captcha image will be given to the players, players need to solve captcha, and send the answer in the chat).
  # CAPTCHA_POSITION -> Falling and Captcha checking concurrently (Player will be kicked, if he fails either falling check or captcha checking).
  # CAPTCHA_ON_POSITION_FAILED -> Initially, the falling check will be started, but if the player fails that check, the captcha checking will be started.
  check-state: CAPTCHA_ON_POSITION_FAILED
  # See "filter-auto-toggle.check-state-toggle".
  check-state-non-toggled: CAPTCHA_ON_POSITION_FAILED
  # See "filter-auto-toggle.check-state-toggle".
  geyser-check-state: CAPTCHA_ON_POSITION_FAILED
  # See "filter-auto-toggle.check-state-toggle".
  geyser-check-state-non-toggled: CAPTCHA_ON_POSITION_FAILED
  load-world: false
  # World file type:
  #  SCHEMATIC (MCEdit .schematic, 1.12.2 and lower, not recommended)
  #  STRUCTURE (structure block .nbt, any Minecraft version is supported, but the latest one is recommended).
  #  WORLDEDIT_SCHEM (WorldEdit .schem, any Minecraft version is supported, but the latest one is recommended).
  world-file-type: STRUCTURE
  world-file-path: "world.nbt"
  # World time in ticks (24000 ticks == 1 in-game day)
  world-ticks: 1000
  # World light level (from 0 to 15)
  world-light-level: 15
  # Should we override block light level (to light up the nether and the end)
  world-override-block-light-level: true
  # Available: ADVENTURE, CREATIVE, SURVIVAL, SPECTATOR
  game-mode: ADVENTURE
  # Unit of time in seconds for the Auto Toggles the Statistics.
  unit-of-time-cps: 300
  # Unit of time in seconds for the Auto Toggles and the Statistics.
  unit-of-time-pps: 5
  # Time in milliseconds how much we should wait before re-enabling logs after attacks
  log-enabler-check-refresh-rate: 1000
  # Duration (in seconds) between regeneration of captchas
  captcha-regenerate-rate: 3600
  # Coordinates for the falling check
  falling-coords:
    x: 0
    y: 512
    z: 0
    teleport-id: 44
  # A "USERNAME - IP" list containing information about players who should join the server without verification.
  whitelisted-players:
    - username: "TestUserAaSsDd777"
      ip: "127.0.0.1"
  # Minimum/maximum total connections amount per the unit of time to toggle anti-bot checks.
  # -1 to disable the check.
  # 0 to enable on any connections per the unit of time.
  filter-auto-toggle:
    # All players will bypass all anti-bot checks
    all-bypass: 0
    # Online mode players will bypass all anti-bot checks.
    # Doesn't work with online-mode-verify: -1
    online-mode-bypass: 49
    # Verify Online Mode connection before AntiBot.
    # If connections per unit of time amount is bigger than the limit: online mode players will need to reconnect.
    # Else: Some attacks can consume more cpu and network, and can lead to long-lasting Mojang rate-limiting.
    # Only works if you have an auth plugin installed. In other cases you should configure need-to-reconnect parameter
    online-mode-verify: 79
    # Toggles check-state/check-state-non-toggled.
    # It is not recommended to enable it, if you want to protect your server from spam-bots.
    # If connections per unit of time amount is bigger than the limit: check-state will be used.
    # Else: check-state-non-toggled will be used.
    check-state-toggle: 0
    # The player will need to reconnect after passing AntiBot check.
    need-to-reconnect: 129
    # Picture in the MOTD Server Ping packet will be disabled.
    disable-motd-picture: 25
    # All the log messages from all plugins will be disabled.
    disable-log: 129
  world-coords:
    x: 0
    y: 0
    z: 0
  captcha-generator:
    # Prepares Captcha packets, consumes x8 more RAM, but improves CPU performance during bot attacks. It's recommended to disable it, if you have less than 2GB of RAM.
    prepare-captcha-packets: false
    # List of paths to the background image to draw on captcha. Any format, 128x128 128x128 px (will be automatically resized and stretched to the correct size). [] if empty.
    backplate-paths:
      - ""
    # Path to the font files to draw on captcha (ttf), can be empty.
    fonts-path:
      - ""
    # Use standard fonts(SANS_SERIF/SERIF/MONOSPACED), use false only if you provide fonts path
    use-standard-fonts: true
    letter-offset-x: 12
    letter-offset-y: 0
    font-letter-spacing-x: -14
    font-letter-spacing-y: 0
    render-font-size: 78.0
    font-letter-width: 44
    font-letter-height: 128
    font-outline: true
    font-rotate: true
    font-ripple: true
    font-ripple-amplitude-width: 100.0
    font-ripple-amplitude-height: 10.0
    font-outline-rate: 1.25
    font-outline-offset-x: -4
    font-outline-offset-y: 4
    font-outline-override-radius: 1
    # Set 0 to disable
    curve-size: 2
    # Set 0 to disable
    curves-amount: 3
    # RGB colors without #
    curves-colors:
      - "000000"
    strikethrough: false
    underline: true
    pattern: "abcdefghijklmnopqrstuvwxyz1234567890"
    # If enabled, both lowercase and uppercase captcha answers entered by players will be correct
    ignore-case: true
    length: 3
    images-count: 1000
    number-spelling: false
    # Set to true if you want to verify the number spelling configuration.
    # The results will be saved to the number_spelling.txt file.
    save-number-spelling-output: false
    each-word-on-separate-line: true
    # If the number ends with any key specified here, the corresponding value will be used.
    # For example: if exception 11 is specified with value 'eleven', the number 411 will be spelt as 'four hundred eleven'.
    number-spelling-exceptions:
      "11": "eleven"
      "12": "twelve"
      "13": "thirteen"
      "14": "fourteen"
      "15": "fifteen"
      "16": "sixteen"
      "17": "seventeen"
      "18": "eighteen"
      "19": "nineteen"
    # null or "" means that the digit should be skipped.
    # Note: all the characters used here (including the space) must be listed in pattern.
    number-spelling-words:
      - - ""
        - "one"
        - "two"
        - "three"
        - "four"
        - "five"
        - "six"
        - "seven"
        - "eight"
        - "nine"
      - - ""
        - "ten"
        - "twenty"
        - "thirty"
        - "forty"
        - "fifty"
        - "sixty"
        - "seventy"
        - "eighty"
        - "ninety"
      - - ""
        - "one hundred"
        - "two hundred"
        - "three hundred"
        - "four hundred"
        - "five hundred"
        - "six hundred"
        - "seven hundred"
        - "eight hundred"
        - "nine hundred"
    rgb-color-list:
      - "000000"
      - "AA0000"
      - "00AA00"
      - "0000AA"
      - "AAAA00"
      - "AA00AA"
      - "00AAAA"
    gradient:
      gradient-enabled: false
      gradients-count: 32
      start-x: 0.0
      start-y: 40.0
      end-x: 128.0
      end-y: 80.0
      start-x-randomness: 0.0
      start-y-randomness: 2.0
      end-x-randomness: 0.0
      end-y-randomness: 2.0
      # Numbers ranging from 0.0 to 1.0 specifying the distribution of colors along the gradient. Can be empty.
      fractions:
        - 0.0
        - 0.1
        - 0.2
        - 0.3
        - 0.4
        - 0.5
        - 0.6
        - 0.7
        - 0.8
        - 0.9
  framed-captcha:
    framed-captcha-enabled: false
    width: 3
    height: 3
    frame-rotation-chance: 0.33
    autoscale-font: true
    coords:
      x: -3
      y: 128
      z: 2
      offset-1-7:
        x: 0
        y: -2
        z: 1
  # Available dimensions: OVERWORLD, NETHER, THE_END
  botfilter-dimension: THE_END
  coords:
    captcha-x: -1.5
    # If your server supports Minecraft 1.7, don't set captcha-y to 0. https://media.discordapp.net/attachments/878241549857738793/915165038464098314/unknown.png
    captcha-y: 128.0
    captcha-z: 0.5
    captcha-yaw: 90.0
    captcha-pitch: 38.0
    falling-check-yaw: 90.0
    falling-check-pitch: 10.0
  tcp-listener:
    # Experimental proxy check feature
    # Checks the proxy via comparing L4 (TCP PSH+ACK -> TCP ACK) and L7 (Minecraft KeepAlive) ping
    # Works better with falling check enabled (150+ falling-check-ticks)
    # Needs libpcap (libpcap-dev) on Linux; WinPcap/npcap on Windows
    # Needs CAP_NET_RAW (or super-user) on Linux
    # Doesn't work if Velocity is behind reverse-proxy (haproxy, protection services, etc)
    proxy-detector-enabled: false
    # Difference between TCP (L4) and Minecraft (L7) ping in milliseconds to detect proxies.
    proxy-detector-difference: 5
    interface-name: "any"
    # How many bytes we should take from the each frame to analyse. 120 is enough for any TCP+IP header analysing
    snaplen: 120
    # How many milliseconds should the delay be between frame analysis.
    listen-delay: 50
    # Time in millis for capturing frames
    timeout: 10
    # Log L4 and L7 ping
    debug-on-fail: false
    debug-on-success: false
  # Available values: FALSE, TRUE, PERMISSION
  #  FALSE - the command will be disallowed
  #  TRUE - the command will be allowed if player has false permission state
  #  PERMISSION - the command will be allowed if player has true permission state
  command-permission-state:
    # Permission: limbofilter.admin.sendfilter
    send-filter: PERMISSION
    # Permission: limbofilter.admin.reload
    reload: PERMISSION
    # Permission: limbofilter.admin.stats
    stats: PERMISSION
    # Permission: limbofilter.admin.help
    help: TRUE
  # Leave title fields empty to disable.
  strings:
    reload: "{PRFX} &aУспешно перезагружено!"
    client-settings-kick: "{PRFX}{NL}&cВаш клиент не отправляет пакеты настроек"
    client-brand-kick: "{PRFX}{NL}&cВаш клиент не отправляет пакет брендов или он заблокирован"
    proxy-check-kick: "{PRFX}{NL}&cВаше соединение подозрительно"
    checking-chat: "{PRFX} Началась проверка бот-фильтра. Пожалуйста, подождите и не двигайтесь..."
    checking-title: "&9Бот-фильтр"
    checking-subtitle: "&aПожалуйста, подождите..."
    checking-captcha-chat: "{PRFX} &aПожалуйста, решите капчу, у вас есть &6{0} &aпопыток"
    checking-wrong-captcha-chat: "{PRFX} &cВы неправильно ввели капчу, у вас осталось &6{0} &cпопыток"
    checking-captcha-title: "&aПожалуйста, решите капчу"
    checking-captcha-subtitle: "&aУ вас есть &6{0} &aпопыток"
    successful-cracked: "{PRFX} &aУспешно пройдена проверка бот-фильтра"
    successful-premium-kick: "{PRFX}{NL}&aУспешно пройдена проверка бот-фильтра.{NL}&6Пожалуйста, перезайдите на сервер!"
    captcha-failed-kick: "{PRFX}{NL}&cВы ошиблись при проверке капчи.{NL}&6Перезайдите на сервер и попробуйте снова"
    falling-check-failed-kick: "{PRFX}{NL}&cПроверка падения не удалась.{NL}&6Пожалуйста, попробуйте присоединиться к серверу снова или свяжитесь с администратором"
    times-up: "{PRFX}{NL}&cВы превысили максимальное время проверки бот-фильтра.{NL}&6Пожалуйста, присоединитесь к серверу"
    stats-format: "&c&lВсего заблокировано: &6&l{0} &c&l| Соединения: &6&l{1}s &c&l| Пинги: &6&l{2}s &c&l| Всего подключений: &6&l{3} &c&l| L7 Пинг: &6&l{4} &c&l| L4 Пинг: &6&l{5}"
    stats-enabled: "{PRFX} &aТеперь вы видите статистику внизу экрана"
    stats-disabled: "{PRFX} &cВы больше не видите статистику внизу экрана"
    send-player-successful: "{PRFX} Игрок {0} успешно отправлен на бот-проверку"
    send-server-successful: "{PRFX} {0} игроков успешно отправлено из {1} на бот-проверку"
    send-failed: "{PRFX} Нет зарегистрированных серверов или подключенных игроков по имени {0}"
    captcha-not-ready-yet: "{PRFX} Капча еще не сгенерировалась, попробуйте через несколько секунд"

Server Info (please complete the following information):

All Limbo plugins versions:
limboapi-1.1.17-SNAPSHOT
limbofilter-1.1.13-SNAPSHOT
limboauth-1.1.13
/velocity dump:

{
  "versionInfo": {
    "name": "Velocity",
    "vendor": "Velocity Contributors",
    "version": "3.2.0-SNAPSHOT (git-67d5e77b-b290)"
  },
  "platform": {
    "operatingSystemType": "Windows Server 2008 R2",
    "operatingSystemVersion": "6.1",
    "operatingSystemArchitecture": "amd64",
    "javaVersion": "17.0.9",
    "javaVendor": "Eclipse Adoptium",
    "listener": {
      "listenerType": "NIO",
      "compression": "Java",
      "encryption": "Java"
    }
  },
  "config": {
    "bind": "10.10.10.9:25565",
    "motd": "\u0026c\u0026lMine\u0026a\u0026l.by",
    "showMaxPlayers": 1000,
    "onlineMode": false,
    "preventClientProxyConnections": false,
    "playerInfoForwardingMode": "BUNGEEGUARD",
    "announceForge": false,
    "onlineModeKickExistingPlayers": true,
    "pingPassthrough": "DISABLED",
    "advanced": {
      "compressionThreshold": 256,
      "compressionLevel": -1,
      "loginRatelimit": 3000,
      "connectionTimeout": 10000,
      "readTimeout": 30000,
      "proxyProtocol": false,
      "tcpFastOpen": false,
      "bungeePluginMessageChannel": true,
      "showPingRequests": false,
      "failoverOnUnexpectedServerDisconnect": true,
      "announceProxyCommands": true,
      "logCommandExecutions": false,
      "logPlayerConnections": true
    },
    "query": {
      "queryEnabled": false,
      "queryPort": 25565,
      "queryMap": "Velocity",
      "showPlugins": false
    },
    "enablePlayerAddressLogging": true,
    "forceKeyAuthentication": true,
    "servers": {
      "Surv": {
        "currentPlayers": 0,
        "host": "10.10.10.9",
        "port": 45685
      },
      "SkyPvP": {
        "currentPlayers": 0,
        "host": "10.10.10.9",
        "port": 45683
      },
      "Tests": {
        "currentPlayers": 0,
        "host": "10.10.10.9",
        "port": 45679
      },
      "Hub": {
        "currentPlayers": 0,
        "host": "10.10.10.9",
        "port": 45680
      },
      "MineZ": {
        "currentPlayers": 0,
        "host": "10.10.10.9",
        "port": 45678
      },
      "Bingo": {
        "currentPlayers": 0,
        "host": "10.10.10.9",
        "port": 45682
      },
      "SkyWars": {
        "currentPlayers": 0,
        "host": "10.10.10.9",
        "port": 45684
      }
    },
    "connectOrder": [
      "Hub"
    ],
    "forcedHosts": {}
  },
  "plugins": [
    {
      "id": "fastmotd",
      "name": "FastMOTD",
      "version": "1.0.4-SNAPSHOT",
      "authors": [
        "Elytrium (https://elytrium.net/)"
      ],
      "description": "MOTD plugin that uses FastPrepareAPI.",
      "url": "https://elytrium.net/"
    },
    {
      "id": "filecleaner",
      "name": "FileCleaner",
      "version": "v2.0.0",
      "authors": [
        "JasonHorkles"
      ],
      "description": "Clean your old files!",
      "url": "https://github.com/SilverstoneMC/FileCleaner"
    },
    {
      "id": "floodgate",
      "name": "floodgate",
      "version": "2.2.2-SNAPSHOT (b87-2876c57)",
      "authors": [
        "GeyserMC"
      ],
      "description": "Allows Bedrock players to join Java edition servers while keeping the server in online mode",
      "url": "https://geysermc.org"
    },
    {
      "id": "geyser",
      "name": "Geyser-Velocity",
      "version": "2.2.0-SNAPSHOT (git-master-3288f42)",
      "authors": [
        "GeyserMC"
      ],
      "url": "https://geysermc.org"
    },
    {
      "id": "limboapi",
      "name": "LimboAPI",
      "version": "1.1.17-SNAPSHOT (git-60c18e5)",
      "authors": [
        "Elytrium (https://elytrium.net/)"
      ],
      "description": "Velocity plugin for making virtual servers.",
      "url": "https://elytrium.net/"
    },
    {
      "id": "limboauth",
      "name": "LimboAuth",
      "version": "1.1.13",
      "authors": [
        "Elytrium (https://elytrium.net/)"
      ],
      "url": "https://elytrium.net/",
      "dependencies": [
        "limboapi",
        "floodgate"
      ]
    },
    {
      "id": "limbofilter",
      "name": "LimboFilter",
      "version": "1.1.13-SNAPSHOT (git-349ef51)",
      "authors": [
        "Elytrium (https://elytrium.net/)"
      ],
      "url": "https://elytrium.net/",
      "dependencies": [
        "limboapi"
      ]
    },
    {
      "id": "luckperms",
      "name": "LuckPerms",
      "version": "5.4.116",
      "authors": [
        "Luck"
      ],
      "description": "A permissions plugin",
      "url": "https://luckperms.net"
    },
    {
      "id": "slashhub",
      "name": "SlashHub",
      "version": "1.5.1",
      "authors": [
        "skygamez"
      ],
      "description": "A Velocity port for SlashHub"
    },
    {
      "id": "spark",
      "name": "spark",
      "version": "1.10.55",
      "authors": [
        "Luck"
      ],
      "description": "spark is a performance profiling plugin/mod for Minecraft clients, servers and proxies."
    },
    {
      "id": "tab",
      "name": "TAB",
      "version": "4.1.2",
      "authors": [
        "NEZNAMY"
      ],
      "description": "An all-in-one solution that works",
      "url": "https://github.com/NEZNAMY/TAB"
    }
  ]
}

Elytrium / LimboFilter

[BUG] No captcha displayed. Only sometimes displayed, but rarely #84