prConcurrentLimit ignored when masterIssue in use

[bytestream]

What Renovate type are you using?

GitLab Self-Hosted

Describe the bug

I added masterIssue: true to the config and it's now bypassed the prConcurrentLimit and created 40+ PRs. Previously it was working perfectly fine.

I did not touch or modify the master issue in anyway that would cause renovate to override the default settings.

Did you see anything helpful in debug logs?

N/A

To Reproduce

renovate.json in the repository:

{
  "$schema": "https://docs.renovatebot.com/renovate-schema.json",
  "extends": [
    "config:base"
  ],
  "prConcurrentLimit": 5,
  "masterIssue": true,
  "stabilityDays": 7,
  "prCreation": "not-pending",
  "rebaseWhen": "never",
  "schedule": [
    "before 10am"
  ]
}

parent config:

module.exports = {
    platform: 'gitlab',
    endpoint: 'https://my.domain.com/api/v4/',
    token: process.env.RENOVATE_TOKEN,

    repositories: [
        'x/y',
    ],

    logLevel: 'debug',

    labels: ["dependencies"],

    requireConfig: true,
    onboarding: true,
    onboardingConfig: {
        extends: ['config:base'],
        prConcurrentLimit: 5
    },

    enabledManagers: [
        'npm',
        'composer'
    ],

    composerIgnorePlatformReqs: false,

    masterIssue: true,
    major: {
        "masterIssueApproval": true
    },

    hostRules: [
        {
            domainName: "github.com",
            token: process.env.GITHUB_COM_TOKEN
        }
    ]
};

Additional context

N/A

[bytestream]

Debug log:

DEBUG: Processing 45 branches: renovate/automattic-woocommerce-3.x, renovate/barryvdh-laravel-cors-1.x, renovate/blueimp-file-upload-10.x, renovate/css-vars-ponyfill-2.x, renovate/dingo-api-2.x, renovate/dingo-api-3.x, renovate/doctrine-dbal-2.x, renovate/endroid-qr-code-3.x, renovate/firebase-php-jwt-5.x, renovate/fntneves-laravel-transactional-events-1.x, renovate/gulp-clean-css-4.x, renovate/gulp-git-2.x, renovate/gulp-shell-0.x, renovate/gulp-zip-5.x, renovate/hideshowpassword-2.x, renovate/jquery-3.x, renovate/jquery-migrate-3.x, renovate/jszip-3.x, renovate/kodeine-laravel-acl-2.x, renovate/laravel-browser-kit-testing-6.x, renovate/laravel-framework-6.x, renovate/laravel-framework-7.x, renovate/laravelcollective-html-6.x, renovate/lg-video-1.x, renovate/lg-zoom-1.x, renovate/lightgallery-1.x, renovate/major-symfony, renovate/overlayscrollbars-1.x, renovate/pdfmake-0.x, renovate/phpunit-phpunit-9.x, renovate/pnotify-4.x, renovate/pnotify-5.x, renovate/pragmarx-google2fa-8.x, renovate/rairlie-laravel-locking-session-1.x, renovate/selectize-0.x, renovate/shepherd.js-7.x, renovate/sweetalert2-8.x, renovate/sweetalert2-9.x, renovate/symfony, renovate/tailwindcss-1.x, renovate/timeago.js-4.x, renovate/tippy.js-6.x, renovate/yadcf-0.x, renovate/yargs-14.x, renovate/yargs-15.x (repository=supportpal/helpdesk)
DEBUG: Calculating hourly PRs remaining (repository=x/y)
DEBUG: currentHourStart=1588924800000 (repository=x/y)
DEBUG: PR hourly limit remaining: 2 (repository=x/y)
DEBUG: Enforcing prConcurrentLimit (5) (repository=x/y)
DEBUG: 23 PRs are currently open (repository=x/y)
DEBUG: PR concurrent limit remaining: -18 (repository=x/y)

Is the issue that those branches already existed but no PR?

[rarkins]

Concurrent limit is based on branches, yes