[Bug]: User acceptance to be an attendee via email invitation

⚠️ 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 user accepts invitation to be an attendee in group calendar to which he belongs to, this event copies to his default invitation calendar where his attendee state remains "Has not responded to admin's invitation yet", and also attendee state remains unchanged ("Has not responded to admin's invitation yet") in group calendar event view.

Organizer shared calendar event state after attendee accepts invitation via email link:

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Attendee calendar overview after invitation accept via email link

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Attendee default invitation calendar event view after invitation accept via email link

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Attendee shared calendar event view after invitation accept via email link

Steps to reproduce

1. Create common user group for organizer and attendee.
2. Create shared calendar for created common group.
3. Create event in shared calendar and add attendee user in attendee list of the event.
4. On attendee side accept invitation for the event via email link.

Expected behavior

After event is accepted via email link attendee state of the user is also accepted by attendee in default invitation and shared calendar views. And there is no need in default invitation calendar event creation if original calendar is shared with this user.

Nextcloud Server version

master

Operating system

Debian/Ubuntu

PHP engine version

None

Web server

None

Database engine version

None

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

List of activated Apps

Nextcloud Signing status

Nextcloud Logs

Additional info

Additional user-backends: OIDC Identity Provider

Reproduce the four listed steps using the email invitation link, then compare the organizer's shared calendar with the attendee's default invitation and shared calendar views. The work is done when accepting the invitation updates the attendee state consistently and does not create an unnecessary default-calendar event when the original calendar is shared.