1.20.1 client is unable to connect to 1.21 servers with server-side ViaFabric Mod

`/viaversion dump` Output

https://dump.viaversion.com/7a7d7d708989f3671d6483228f7afcfdeb375d6fc8de5051fac3bd77f9114ce0

Console Error

Client:

Internal Exception: io.netty.handler.codec.DecoderException: 
java.io.IOException: Packet play/clientbound/minecraft:custom_payload 
(class_2658) was larger than I expected, found 20 bytes extra whilst 
reading packet clientbound/minecraft:custom_payload

Bug Description

An error occurred when trying to connect to the 1.20.1 server with ViaFabric Server-Side Mod using the vanilla 1.21 client.

I have tested all mods in the server and none of them force the client to install (i.e. you can establish a connection using the 1.20.1 Vanilla client).

No server-side mods tried to add an entity that vanilla doesn't have either.

No matter whether this server is running under the Velocity or not, it cannot be connected.

The same error occurs when the ViaFabric Mod on the server is deleted and the ViaFabricPlus client Mod is used.

Steps to Reproduce

Boot up 1.20.1 server with ViaFabric Server-side Mod,
Connect to the server with 1.21 Vanilla Client,
The Problem Occured.

Expected Behavior

At the very least, it should allow the player to establish a connection instead of causing an error.

Additional Server Info

Server: Minecraft 1.20.1 + Fabric 0.16.7

Mod List

[10:53:45] [main/INFO]: Loading 106 mods:
        - better_log4j_config 1.2.0
        - carpet 1.4.112+v230608
        - carpet-tis-addition 1.63.0
           \-- conditional-mixin 0.6.2
        - fabric-api 0.92.2+1.20.1
           |-- fabric-api-base 0.4.31+1802ada577
           |-- fabric-api-lookup-api-v1 1.6.36+1802ada577
           |-- fabric-biome-api-v1 13.0.13+1802ada577
           |-- fabric-block-api-v1 1.0.11+1802ada577
           |-- fabric-block-view-api-v2 1.0.1+1802ada577
           |-- fabric-blockrenderlayer-v1 1.1.41+1802ada577
           |-- fabric-client-tags-api-v1 1.1.2+1802ada577
           |-- fabric-command-api-v1 1.2.34+f71b366f77
           |-- fabric-command-api-v2 2.2.13+1802ada577
           |-- fabric-commands-v0 0.2.51+df3654b377
           |-- fabric-containers-v0 0.1.64+df3654b377
           |-- fabric-content-registries-v0 4.0.11+1802ada577
           |-- fabric-convention-tags-v1 1.5.5+1802ada577
           |-- fabric-crash-report-info-v1 0.2.19+1802ada577
           |-- fabric-data-attachment-api-v1 1.0.0+de0fd6d177
           |-- fabric-data-generation-api-v1 12.3.4+1802ada577
           |-- fabric-dimensions-v1 2.1.54+1802ada577
           |-- fabric-entity-events-v1 1.6.0+1c78457f77
           |-- fabric-events-interaction-v0 0.6.2+1802ada577
           |-- fabric-events-lifecycle-v0 0.2.63+df3654b377
           |-- fabric-game-rule-api-v1 1.0.40+1802ada577
           |-- fabric-item-api-v1 2.1.28+1802ada577
           |-- fabric-item-group-api-v1 4.0.12+1802ada577
           |-- fabric-key-binding-api-v1 1.0.37+1802ada577
           |-- fabric-keybindings-v0 0.2.35+df3654b377
           |-- fabric-lifecycle-events-v1 2.2.22+1802ada577
           |-- fabric-loot-api-v2 1.2.1+1802ada577
           |-- fabric-loot-tables-v1 1.1.45+9e7660c677
           |-- fabric-message-api-v1 5.1.9+1802ada577
           |-- fabric-mining-level-api-v1 2.1.50+1802ada577
           |-- fabric-model-loading-api-v1 1.0.3+1802ada577
           |-- fabric-models-v0 0.4.2+9386d8a777
           |-- fabric-networking-api-v1 1.3.11+1802ada577
           |-- fabric-networking-v0 0.3.51+df3654b377
           |-- fabric-object-builder-api-v1 11.1.3+1802ada577
           |-- fabric-particles-v1 1.1.2+1802ada577
           |-- fabric-recipe-api-v1 1.0.21+1802ada577
           |-- fabric-registry-sync-v0 2.3.3+1802ada577
           |-- fabric-renderer-api-v1 3.2.1+1802ada577
           |-- fabric-renderer-indigo 1.5.2+85287f9f77
           |-- fabric-renderer-registries-v1 3.2.46+df3654b377
           |-- fabric-rendering-data-attachment-v1 0.3.37+92a0d36777
           |-- fabric-rendering-fluids-v1 3.0.28+1802ada577
           |-- fabric-rendering-v0 1.1.49+df3654b377
           |-- fabric-rendering-v1 3.0.8+1802ada577
           |-- fabric-resource-conditions-api-v1 2.3.8+1802ada577
           |-- fabric-resource-loader-v0 0.11.10+1802ada577
           |-- fabric-screen-api-v1 2.0.8+1802ada577
           |-- fabric-screen-handler-api-v1 1.3.30+1802ada577
           |-- fabric-sound-api-v1 1.0.13+1802ada577
           |-- fabric-transfer-api-v1 3.3.5+8dd72ea377
           \-- fabric-transitive-access-wideners-v1 4.3.1+1802ada577
        - fabric-language-kotlin 1.12.3+kotlin.2.0.21
           |-- org_jetbrains_kotlin_kotlin-reflect 2.0.21
           |-- org_jetbrains_kotlin_kotlin-stdlib 2.0.21
           |-- org_jetbrains_kotlin_kotlin-stdlib-jdk7 2.0.21
           |-- org_jetbrains_kotlin_kotlin-stdlib-jdk8 2.0.21
           |-- org_jetbrains_kotlinx_atomicfu-jvm 0.25.0
           |-- org_jetbrains_kotlinx_kotlinx-coroutines-core-jvm 1.9.0
           |-- org_jetbrains_kotlinx_kotlinx-coroutines-jdk8 1.9.0
           |-- org_jetbrains_kotlinx_kotlinx-datetime-jvm 0.6.1
           |-- org_jetbrains_kotlinx_kotlinx-io-bytestring-jvm 0.5.4
           |-- org_jetbrains_kotlinx_kotlinx-io-core-jvm 0.5.4
           |-- org_jetbrains_kotlinx_kotlinx-serialization-cbor-jvm 1.7.3
           |-- org_jetbrains_kotlinx_kotlinx-serialization-core-jvm 1.7.3
           \-- org_jetbrains_kotlinx_kotlinx-serialization-json-jvm 1.7.3
        - fabric_proxy 1.8.0
           \-- com_moandjiezana_toml_toml4j 0.7.2
        - fabricloader 0.16.7
           \-- mixinextras 0.4.1
        - ferritecore 6.0.1
        - gca mc1.20.1-2.8.0+build.55
        - huskhomes 4.7
           |-- adventure-platform-fabric 5.9.0
           |    |-- net_kyori_adventure-api 4.14.0
           |    |-- net_kyori_adventure-key 4.14.0
           |    |-- net_kyori_adventure-platform-api 4.3.0
           |    |-- net_kyori_adventure-text-logger-slf4j 4.14.0
           |    |-- net_kyori_adventure-text-minimessage 4.14.0
           |    |-- net_kyori_adventure-text-serializer-ansi 4.14.0
           |    |-- net_kyori_adventure-text-serializer-gson 4.14.0
           |    |-- net_kyori_adventure-text-serializer-json 4.14.0
           |    |-- net_kyori_adventure-text-serializer-plain 4.14.0
           |    |-- net_kyori_ansi 1.0.2
           |    |-- net_kyori_examination-api 1.3.0
           |    \-- net_kyori_examination-string 1.3.0
           |-- com_h2database_h2 2.2.220
           |-- com_mysql_mysql-connector-j 8.4.0
           |-- fabric-permissions-api-v0 0.3.1
           |-- net_impactdev_impactor_api_economy_dev-slim 5.2.3-SNAPSHOT
           |-- org_apache_commons_commons-pool2 2.12.0
           |-- org_mariadb_jdbc_mariadb-java-client 3.4.0
           |-- org_xerial_sqlite-jdbc 3.46.0.0
           |-- placeholder-api 2.1.3+1.20.1
           \-- redis_clients_jedis 5.1.3
        - java 17
        - lazydfu 0.1.3
        - ledger 1.2.8
           \-- server_translations_api 2.0.0-beta.2+1.19.4-pre2
                \-- packet_tweaker 0.3.1+23w06a
        - lithium 0.11.2
        - luckperms 5.4.102
        - minecraft 1.20.1
        - nochatreports 1.20.1-v2.2.2
           |-- fabric-rendering-v1 3.0.6+b3afc78b82
           \-- fabric-screen-api-v1 2.0.6+b3afc78b82
        - servux 0.1.0
        - skinrestorer 2.1.0+1.20-fabric
        - spark 1.10.53
        - starlight 1.1.2+fabric.dbc156f
        - syncmatica 1.20.1-0.3.11
        - viafabric 0.4.15+84-main
           |-- cotton-client-commands 1.1.0+1.15.2
           |-- viafabric-mc1201 0.4.15+84-main
           \-- viaversion 5.0.4-SNAPSHOT
        - xaerominimap 24.5.0
        - xaeroworldmap 1.39.0

Checklist

[X] I have checked if this is specific to ViaFabric platform, and doesn't happen when running it on other platforms (Paper/Sponge/Velocity/Waterfall).
[X] I have included a ViaVersion dump.
[X] If applicable, I have included a paste (not a screenshot) of the error.
[X] I have tried the latest build(s) from https://ci.viaversion.com/ and the issue still persists.

ViaVersion / ViaFabric