[Bug]: Initials avatars not adapting to light/dark theme setting

⚠️ 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

In Nextcloud, users can choose between a light or dark theme. Automatically generated avatars (with initials) are expected to follow this setting, adapting their background color accordingly (light or dark).

In my case, my system is set to dark mode, and the avatars remain stuck in dark mode regardless of the theme selected in Nextcloud (whether set to follow the system theme, light, or dark).

Below is a screenshot illustrating the issue, with Nextcloud set to light theme while the system is in dark mode.

If I switch my system to light mode, the avatars then switch to light mode as well, even though the Nextcloud theme is still explicitly set to light mode.

Steps to reproduce

1. Set the operating system to dark mode.
2. Open Nextcloud in a web browser.
3. Set Nextcloud’s theme to light mode (not “follow system”).
4. Open a folder with a file shared with another user.
5. Observe the automatically generated avatar (initials) of the shared user.

Expected behavior

The avatar appears in dark mode instead of adapting to the light theme.

Nextcloud Server version

33

Operating system

Debian/Ubuntu

PHP engine version

PHP 8.3

Web server

Apache (supported)

Database engine version

MariaDB

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

None

Are you using the Nextcloud Server Encryption module?

None

What user-backends are you using?

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

Configuration report

{
    "system": {
        "passwordsalt": "***REMOVED SENSITIVE VALUE***",
        "secret": "***REMOVED SENSITIVE VALUE***",
        "trusted_domains": [
            "***REMOVED SENSITIVE VALUE***"
        ],
        "trusted_proxies": "***REMOVED SENSITIVE VALUE***",
        "forwarded_for_headers": [
            "HTTP_X_FORWARDED_FOR"
        ],
        "datadirectory": "***REMOVED SENSITIVE VALUE***",
        "dbtype": "mysql",
        "version": "33.0.2.2",
        "overwrite.cli.url": "***REMOVED SENSITIVE VALUE***",
        "htaccess.RewriteBase": "\/",
        "dbname": "***REMOVED SENSITIVE VALUE***",
        "dbhost": "***REMOVED SENSITIVE VALUE***",
        "dbport": "",
        "dbtableprefix": "oc_",
        "mysql.utf8mb4": true,
        "dbuser": "***REMOVED SENSITIVE VALUE***",
        "dbpassword": "***REMOVED SENSITIVE VALUE***",
        "installed": true,
        "memcache.local": "\\OC\\Memcache\\Redis",
        "memcache.locking": "\\OC\\Memcache\\Redis",
        "memcache.distributed": "\\OC\\Memcache\\Redis",
        "redis": {
            "host": "***REMOVED SENSITIVE VALUE***",
            "port": 0,
            "timeout": 0
        },
        "filelocking.enabled": true,
        "instanceid": "***REMOVED SENSITIVE VALUE***",
        "ldapIgnoreNamingRules": false,
        "ldapProviderFactory": "OCA\\User_LDAP\\LDAPProviderFactory",
        "maintenance": false,
        "theme": "",
        "loglevel": 0,
        "default_phone_region": "FR",
        "mail_smtpmode": "smtp",
        "mail_sendmailmode": "smtp",
        "mail_from_address": "***REMOVED SENSITIVE VALUE***",
        "mail_domain": "***REMOVED SENSITIVE VALUE***",
        "mail_smtphost": "***REMOVED SENSITIVE VALUE***",
        "mail_smtpport": "465",
        "mail_smtpsecure": "ssl",
        "mail_smtpauthtype": "LOGIN",
        "mail_smtpauth": 1,
        "mail_smtpname": "***REMOVED SENSITIVE VALUE***",
        "mail_smtppassword": "***REMOVED SENSITIVE VALUE***",
        "maintenance_window_start": 4,
        "app_install_overwrite": [
            "richdocuments",
            "files_rightclick",
            "keeweb"
        ]
    }
}

List of activated Apps

Enabled:
  - activity: 6.0.0
  - app_api: 33.0.0
  - bookmarks: 16.1.3
  - bruteforcesettings: 6.0.0
  - calendar: 6.2.2
  - circles: 33.0.0
  - cloud_federation_api: 1.17.0
  - comments: 1.23.0
  - contacts: 8.4.3
  - contactsinteraction: 1.14.1
  - dashboard: 7.13.0
  - dav: 1.36.0
  - encryption: 2.21.0
  - external: 8.0.0
  - federatedfilesharing: 1.23.0
  - federation: 1.23.0
  - files: 2.5.0
  - files_downloadlimit: 5.1.0
  - files_external: 1.25.1
  - files_pdfviewer: 6.0.0
  - files_reminders: 1.6.0
  - files_sharing: 1.25.2
  - files_trashbin: 1.23.0
  - files_versions: 1.26.0
  - firstrunwizard: 6.0.0
  - keeweb: 0.6.22
  - logreader: 6.0.0
  - lookup_server_connector: 1.21.0
  - nextcloud_announcements: 5.0.0
  - notes: 4.13.1
  - notifications: 6.0.0
  - notify_push: 1.3.1
  - oauth2: 1.21.0
  - password_policy: 5.0.0
  - photos: 6.0.0
  - privacy: 5.0.0
  - profile: 1.2.0
  - provisioning_api: 1.23.0
  - recommendations: 6.0.0
  - related_resources: 4.0.0
  - richdocuments: 10.1.2
  - serverinfo: 5.0.0
  - settings: 1.16.0
  - sharebymail: 1.23.0
  - support: 5.0.0
  - survey_client: 5.0.0
  - suspicious_login: 11.0.0
  - systemtags: 1.23.0
  - text: 7.0.0
  - theming: 2.8.0
  - twofactor_backupcodes: 1.22.0
  - twofactor_totp: 15.0.0
  - updatenotification: 1.23.0
  - user_ldap: 1.24.0
  - user_status: 1.13.0
  - viewer: 6.0.0
  - weather_status: 1.13.0
  - webhook_listeners: 1.5.0
  - workflowengine: 2.15.0
Disabled:
  - admin_audit: 1.23.0
  - files_rightclick: 0.15.1 (installed 0.15.1)
  - testing: 1.23.0
  - twofactor_nextcloud_notification: 7.0.0

Nextcloud Signing status

No errors have been found.

Nextcloud Logs

Additional info

No response

The report names no source file or test. Reproduce the issue by switching the operating system to dark mode, setting Nextcloud to light mode, and opening a folder with a shared file; trace the generated initials avatar and theme handling. Done means the avatar follows the selected Nextcloud theme rather than the operating-system theme, with coverage for the reported settings.