Can't stop sharing to old unexistent group

[Thatoo]

Steps to reproduce

1. Share a calendar to group 1
2. Share calendar to group 2
3. Delete group 1
4. Edit calendar
5. Group 1 is still listed as a group to whom the calendar is shared
6. Click on the bin icon to stop sharing to group 1
7. Save
8. Refresh the page
9. Edit calendar
10. Group 1 is still listed as a group to whom the calendar is shared

Expected behavior

The calendar should not be shared to group 1 as soon as group 1 has been deleted
and
if not, it should be possible to stop sharing to group 1 even though it doesn't exist anymore.

Actual behavior

The calendar is shared to group 1, a group that doesn't exist anymore

Calendar app version

5.5.9

CalDAV-clients used

No response

Browser

Firefox 145.0.1

Client operating system

NixOS 25.11

Server operating system

Debian 12

Web server

Nginx

Database engine version

MySQL

PHP engine version

PHP 8.3

Nextcloud version

31.0.10

Updated from an older installed version or fresh install

None

List of activated apps

Enabled:
  - activity: 4.0.0
  - app_api: 5.0.2
  - appointments: 2.6.1
  - bookmarks: 15.2.0
  - bruteforcesettings: 4.0.0
  - calendar: 5.5.9
  - circles: 31.0.0
  - cloud_federation_api: 1.14.0
  - collectives: 3.2.3
  - comments: 1.21.0
  - contacts: 7.3.4
  - cookbook: 0.11.4
  - dashboard: 7.11.0
  - dav: 1.33.0
  - deck: 1.15.3
  - federatedfilesharing: 1.21.0
  - federation: 1.21.0
  - files: 2.3.1
  - files_downloadlimit: 4.0.0
  - files_pdfviewer: 4.0.0
  - files_photospheres: 1.31.1
  - files_reminders: 1.4.0
  - files_sharing: 1.23.1
  - files_trashbin: 1.21.0
  - files_versions: 1.24.0
  - firstrunwizard: 4.0.0
  - forms: 5.2.2
  - logreader: 4.0.0
  - lookup_server_connector: 1.19.0
  - maps: 1.6.0
  - nextcloud_announcements: 3.0.0
  - notes: 4.12.3
  - notifications: 4.0.0
  - oauth2: 1.19.1
  - password_policy: 3.0.0
  - passwords: 2025.10.20
  - photos: 4.0.0
  - polls: 8.5.0
  - privacy: 3.0.0
  - profile: 1.0.0
  - provisioning_api: 1.21.0
  - quota_warning: 1.22.0
  - recommendations: 4.0.0
  - related_resources: 2.0.0
  - richdocuments: 8.7.6
  - 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
  - tasks: 0.17.0
  - text: 5.0.2
  - theming: 2.6.1
  - twofactor_backupcodes: 1.20.0
  - user_ldap: 1.22.0
  - user_status: 1.11.0
  - viewer: 4.0.0
  - weather_status: 1.11.0
  - webhook_listeners: 1.2.0
  - workflowengine: 2.13.0
Disabled:
  - accessibility: 1.10.0
  - admin_audit: 1.21.0
  - contactsinteraction: 1.12.1 (installed 1.6.0)
  - cospend: 3.1.6 (installed 3.1.6)
  - encryption: 2.19.0
  - files_external: 1.23.0 (installed 1.13.0)
  - files_mindmap: 0.0.33 (installed 0.0.33)
  - gestion: 2.8.7 (installed 2.8.7)
  - keeweb: 0.6.22 (installed 0.6.22)
  - mail: 5.5.11 (installed 5.5.11)
  - riotchat: 0.19.0 (installed 0.19.0)
  - sharereview: 1.4.0 (installed 1.4.0)
  - suspicious_login: 9.0.1
  - twofactor_nextcloud_notification: 5.0.0
  - twofactor_totp: 13.0.0-dev.0
  - updatenotification: 1.21.0 (installed 1.12.0)

Nextcloud configuration

{
    "system": {
        "passwordsalt": "***REMOVED SENSITIVE VALUE***",
        "secret": "***REMOVED SENSITIVE VALUE***",
        "trusted_domains": [
            "localhost",
            "nextcloud.domain.tld"
        ],
        "datadirectory": "***REMOVED SENSITIVE VALUE***",
        "dbtype": "mysql",
        "version": "31.0.10.2",
        "overwrite.cli.url": "https:\/\/nextcloud.domain.tld\/",
        "dbname": "***REMOVED SENSITIVE VALUE***",
        "dbhost": "***REMOVED SENSITIVE VALUE***",
        "dbport": "",
        "dbtableprefix": "oc_",
        "mysql.utf8mb4": true,
        "dbuser": "***REMOVED SENSITIVE VALUE***",
        "dbpassword": "***REMOVED SENSITIVE VALUE***",
        "installed": true,
        "instanceid": "***REMOVED SENSITIVE VALUE***",
        "ldapProviderFactory": "OCA\\User_LDAP\\LDAPProviderFactory",
        "updatechecker": false,
        "memcache.local": "\\OC\\Memcache\\APCu",
        "integrity.check.disabled": true,
        "filelocking.enabled": true,
        "memcache.locking": "\\OC\\Memcache\\Redis",
        "redis": {
            "host": "***REMOVED SENSITIVE VALUE***",
            "port": "6379",
            "timeout": "0.0",
            "password": "***REMOVED SENSITIVE VALUE***"
        },
        "hashing_default_password": true,
        "localstorage.allowsymlinks": true,
        "logout_url": "https:\/\/domain.tld\/yunohost\/sso\/?action=logout&r=aHR0cHM6Ly9uZXh0Y2xvdWQubGVzdG9pdHNwYXJ0YWdlcy5mci8=",
        "maintenance": false,
        "loglevel": 2,
        "simpleSignUpLink.shown": false,
        "enable_previews": true,
        "preview_max_x": 1080,
        "preview_max_y": 1920,
        "jpeg_quality": 90,
        "mail_from_address": "***REMOVED SENSITIVE VALUE***",
        "mail_smtpmode": "smtp",
        "mail_sendmailmode": "smtp",
        "mail_domain": "***REMOVED SENSITIVE VALUE***",
        "mail_smtphost": "***REMOVED SENSITIVE VALUE***",
        "mail_smtpauth": 1,
        "mail_smtpname": "***REMOVED SENSITIVE VALUE***",
        "mail_smtppassword": "***REMOVED SENSITIVE VALUE***",
        "mail_smtpport": "25",
        "mail_smtpstreamoptions": {
            "ssl": {
                "allow_self_signed": true,
                "verify_peer": false,
                "verify_peer_name": false
            }
        },
        "theme": "",
        "logfile": "\/var\/log\/nextcloud\/nextcloud.log",
        "maintenance_window_start": 1,
        "trusted_proxies": "***REMOVED SENSITIVE VALUE***",
        "lost_password_link": "https:\/\/domain.tld\/yunohost\/sso\/password.html",
        "trashbin_retention_obligation": "auto, 30",
        "versions_retention_obligation": "auto, 30",
        "default_phone_region": ""
    }
}

Web server error log

Log file

Browser log

Additional info

No response

[SebastianKrupinski]

Confirmed

[max65482]

This needs to be fixed in server. Opened PR nextcloud/server#57075.