[Bug]: group dropdown in new account dialog does not work

⚠️ This issue respects the following points: ⚠️

• This is a bug, not a question or a configuration/webserver/proxy issue.
• This issue is not already reported on Github OR Nextcloud Community Forum (I've searched it).
• Nextcloud Server is up to date. See Maintenance and Release Schedule for supported versions.
• I agree to follow Nextcloud's Code of Conduct.

Bug description

When creating a new account, the group dropdown is empty. Once the account is added, the group can be added by editing the account.

Steps to reproduce

1. go to /settings/users
2. click 'New account'
3. click the dropdown for group membership. No results are shown
4. start typing the name of an existing group. No 'autocomplete' results are shown.

Expected behavior

I'd expect the dropdown to contain some groups when opened, possibly amended when there's many groups when typing in the first few characters of the group name.

Nextcloud Server version

31

Operating system

Other

PHP engine version

PHP 8.3

Web server

Nginx

Database engine version

MariaDB

Is this bug present after an update or on a fresh install?

Upgraded to a MAJOR version (ex. 31 to 32)

Are you using the Nextcloud Server Encryption module?

Encryption is Disabled

What user-backends are you using?

• Default user-backend (database)
• LDAP/ Active Directory
• SSO - SAML
• Other

Configuration report

{
    "system": {
        "apps_paths": [
            {
                "path": "\/nix\/store\/pl1jb62iayjdmzbndvhm3qnrfmymp62g-nextcloud-31.0.5-with-apps\/apps",
                "url": "\/apps",
                "writable": false
            },
            {
                "path": "\/nix\/store\/pl1jb62iayjdmzbndvhm3qnrfmymp62g-nextcloud-31.0.5-with-apps\/nix-apps",
                "url": "\/nix-apps",
                "writable": false
            },
            {
                "path": "\/nix\/store\/pl1jb62iayjdmzbndvhm3qnrfmymp62g-nextcloud-31.0.5-with-apps\/store-apps",
                "url": "\/store-apps",
                "writable": true
            }
        ],
        "appstoreenabled": false,
        "memcache.local": "\\OC\\Memcache\\APCu",
        "dbname": "***REMOVED SENSITIVE VALUE***",
        "dbhost": "***REMOVED SENSITIVE VALUE***",
        "dbuser": "***REMOVED SENSITIVE VALUE***",
        "dbtype": "mysql",
        "datadirectory": "***REMOVED SENSITIVE VALUE***",
        "default_language": "nl",
        "default_phone_region": "nl",
        "default_timezone": "Europe\/Amsterdam",
        "force_language": "nl",
        "knowledgebaseenabled": false,
        "log_type": "syslog",
        "loglevel": 2,
        "logo_url": "https:\/\/cloud.eicas.nl",
        "mail_smtpmode": "disabled",
        "maintenance_window_start": "1",
        "overwriteprotocol": "",
        "profile.enabled": false,
        "skeletondirectory": "",
        "trusted_proxies": "***REMOVED SENSITIVE VALUE***",
        "passwordsalt": "***REMOVED SENSITIVE VALUE***",
        "secret": "***REMOVED SENSITIVE VALUE***",
        "instanceid": "***REMOVED SENSITIVE VALUE***",
        "version": "31.0.5.1",
        "overwrite.cli.url": "http:\/\/localhost",
        "dbport": "",
        "dbtableprefix": "oc_",
        "mysql.utf8mb4": true,
        "dbpassword": "***REMOVED SENSITIVE VALUE***",
        "installed": true,
        "maintenance": false,
        "upgrade": {
            "disable-web": true
        },
        "upgrade.disable-web": true,
        "integrity.check.disabled": true,
        "trusted_domains": [
            "cloud.eicas.nl"
        ]
    }
}

List of activated Apps

Enabled:
  - activity: 4.0.0
  - app_api: 5.0.2
  - bruteforcesettings: 4.0.0
  - calendar: 5.2.4
  - cloud_federation_api: 1.14.0
  - comments: 1.21.0
  - contactsinteraction: 1.12.0
  - dav: 1.33.0
  - deck: 1.15.1
  - external: 6.0.2
  - federatedfilesharing: 1.21.0
  - federation: 1.21.0
  - files: 2.3.1
  - files_downloadlimit: 4.0.0
  - files_pdfviewer: 4.0.0
  - files_reminders: 1.4.0
  - files_sharing: 1.23.1
  - files_trashbin: 1.21.0
  - files_versions: 1.24.0
  - groupfolders: 19.0.4
  - logreader: 4.0.0
  - lookup_server_connector: 1.19.0
  - nextcloud_announcements: 3.0.0
  - notifications: 4.0.0
  - oauth2: 1.19.1
  - onlyoffice: 9.8.0
  - password_policy: 3.0.0
  - privacy: 3.0.0
  - profile: 1.0.0
  - provisioning_api: 1.21.0
  - recommendations: 4.0.0
  - related_resources: 2.0.0
  - serverinfo: 3.0.0
  - settings: 1.14.0
  - sharebymail: 1.21.0
  - support: 3.0.0
  - survey_client: 3.0.0
  - systemtags: 1.21.1
  - text: 5.0.0
  - theming: 2.6.1
  - theming_customcss: 1.18.0
  - twofactor_backupcodes: 1.20.0
  - twofactor_totp: 13.0.0-dev.0
  - updatenotification: 1.21.0
  - user_status: 1.11.0
  - viewer: 4.0.0
  - weather_status: 1.11.0
  - webhook_listeners: 1.2.0
  - workflowengine: 2.13.0
Disabled:
  - admin_audit: 1.21.0
  - circles: 31.0.0 (installed 25.0.0)
  - dashboard: 7.11.0 (installed 7.4.0)
  - encryption: 2.19.0
  - files_external: 1.23.0
  - firstrunwizard: 4.0.0 (installed 3.0.0)
  - photos: 4.0.0-dev.1 (installed 1.6.0)
  - suspicious_login: 9.0.1
  - twofactor_nextcloud_notification: 5.0.0
  - user_ldap: 1.22.0

Nextcloud Signing status

Nextcloud Logs

Additional info

OS: NixOS Unstable

Start at the Settings users page and the New account dialog described in the reproduction steps, then trace how group membership options and autocomplete results are loaded. The issue is done when existing groups appear on opening the dropdown and matching groups appear while typing, with the relevant user-management behavior covered by a regression check.