[Bug]: No calendar event email/notification when event content is updated

⚠️ 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 updating content fields of a calendar event (such as the summary, location, link, description, etc.), no email/notification with the updated event is sent to the event participants. As a user, I expect that participants of my event receive an email/notification, when I, e.g., change the location of the event, or when I update the link/url of an event that is supposed to be an online call.

The only way which works and where I can trigger an email/notification is when I update the date/time of the event (e.g. by making the event a minute longer), in addition to updating the content of the event. Another workaround is deleting the event and creating a new event with the updated content. However, this might confuse event participants, because they first receive an email/notification that the original event is cancelled.

Steps to reproduce

1. Create a calendar event with a participant --> invite email/notification is sent to participant.
2. Update a content field of the event (such as the location or link/url --> no update email/notification is sent to participant.

Expected behavior

1. As the participant, receive an email/notification with the invitation to the calendar event.
2. Receive an email/notification with the updated calendar event.

Installation method

Community Docker image

Nextcloud Server version

27

Operating system

None

PHP engine version

None

Web server

Nginx

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***",
        "version": "27.1.2.1",
        "dbtableprefix": "oc_",
        "mysql.utf8mb4": true,
        "installed": true,
        "instanceid": "***REMOVED SENSITIVE VALUE***",
        "ldapIgnoreNamingRules": false,
        "ldapProviderFactory": "OCA\\User_LDAP\\LDAPProviderFactory",
        "maintenance": false,
        "loglevel": 2,
        "app_install_overwrite": [
            "groupfolders",
            "passwords"
        ],
        "theme": "",
        "memcache.local": "\\OC\\Memcache\\APCu",
        "apps_paths": [
            {
                "path": "\/var\/www\/html\/apps",
                "url": "\/apps",
                "writable": false
            },
            {
                "path": "\/var\/www\/html\/custom_apps",
                "url": "\/custom_apps",
                "writable": true
            }
        ],
        "dbtype": "mysql",
        "dbname": "***REMOVED SENSITIVE VALUE***",
        "dbuser": "***REMOVED SENSITIVE VALUE***",
        "dbpassword": "***REMOVED SENSITIVE VALUE***",
        "dbhost": "***REMOVED SENSITIVE VALUE***",
        "datadirectory": "***REMOVED SENSITIVE VALUE***",
        "memcache.distributed": "\\OC\\Memcache\\Redis",
        "memcache.locking": "\\OC\\Memcache\\Redis",
        "redis": {
            "host": "***REMOVED SENSITIVE VALUE***",
            "password": "***REMOVED SENSITIVE VALUE***",
            "port": 6379
        },
        "trusted_proxies": "***REMOVED SENSITIVE VALUE***",
        "mail_smtpmode": "smtp",
        "mail_smtphost": "***REMOVED SENSITIVE VALUE***",
        "mail_smtpport": "25",
        "mail_smtpsecure": "tls",
        "mail_smtpauth": false,
        "mail_smtpauthtype": "PLAIN",
        "mail_smtpname": "***REMOVED SENSITIVE VALUE***",
        "mail_from_address": "***REMOVED SENSITIVE VALUE***",
        "mail_domain": "***REMOVED SENSITIVE VALUE***",
        "mail_smtppassword": "***REMOVED SENSITIVE VALUE***"
    }
}

List of activated Apps

Enabled:
  - activity: 2.19.0
  - admin_audit: 1.17.0
  - auto_groups: 1.5.2
  - bruteforcesettings: 2.7.0
  - calendar: 4.5.2
  - cloud_federation_api: 1.10.0
  - contacts: 5.4.2
  - dav: 1.27.0
  - federatedfilesharing: 1.17.0
  - files: 1.22.0
  - files_pdfviewer: 2.8.0
  - files_reminders: 1.0.0
  - files_rightclick: 1.6.0
  - files_sharing: 1.19.0
  - files_trashbin: 1.17.0
  - files_versions: 1.20.0
  - groupfolders: 15.3.1
  - impersonate: 1.14.0
  - logreader: 2.12.0
  - lookup_server_connector: 1.15.0
  - mail: 3.4.3
  - notifications: 2.15.0
  - oauth2: 1.15.1
  - passwords: 2023.10.30
  - provisioning_api: 1.17.0
  - recommendations: 1.6.0
  - richdocuments: 8.2.1
  - settings: 1.9.0
  - spreed: 17.1.1
  - text: 3.8.0
  - theming: 2.2.0
  - twofactor_backupcodes: 1.16.0
  - updatenotification: 1.17.0
  - user_ldap: 1.17.0
  - viewer: 2.1.0
  - workflowengine: 2.9.0
Disabled:
  - circles: 27.0.1 (installed 26.0.0)
  - comments: 1.17.0 (installed 1.16.0)
  - contactsinteraction: 1.8.0 (installed 1.7.0)
  - dashboard: 7.7.0 (installed 7.6.0)
  - encryption: 2.15.0
  - federation: 1.17.0 (installed 1.16.0)
  - files_external: 1.19.0 (installed 1.19.0)
  - firstrunwizard: 2.16.0 (installed 2.15.0)
  - nextcloud_announcements: 1.16.0 (installed 1.15.0)
  - password_policy: 1.17.0 (installed 1.16.0)
  - photos: 2.3.0 (installed 2.2.0)
  - privacy: 1.11.0 (installed 1.10.0)
  - related_resources: 1.2.0 (installed 1.1.0-alpha1)
  - serverinfo: 1.17.0 (installed 1.16.0)
  - sharebymail: 1.17.0 (installed 1.16.0)
  - support: 1.10.0 (installed 1.9.0)
  - survey_client: 1.15.0 (installed 1.14.0)
  - suspicious_login: 5.0.0
  - systemtags: 1.17.0 (installed 1.16.0)
  - twofactor_totp: 9.0.0
  - user_status: 1.7.0 (installed 1.6.0)
  - weather_status: 1.7.0 (installed 1.6.0)

Nextcloud Signing status

No errors have been found.

Nextcloud Logs

No response

Additional info

No response

Start by tracing the calendar event update path and the email/notification dispatch used when an event's date or time changes. Reproduce the reported location or link update and compare it with a date/time update. Done means participants receive an updated event email or notification when content fields change.