Existing events not shareable for edits with another user

[Jeetah]

Steps to reproduce

1. Import calendar
2. Share it incl edit with another user
3. This user can only delete exiting ones - not edit

Expected behavior

Other user should have full edit/delete rights if set so - also for existing events.

Actual behavior

Other user can only delete

Calendar app version

6.2.1

CalDAV-clients used

DAVx5

Browser

No response

Client operating system

No response

Server operating system

No response

Web server

None

Database engine version

None

PHP engine version

None

Nextcloud version

25

Updated from an older installed version or fresh install

None

List of activated apps

Nextcloud configuration

Web server error log

Log file

Browser log

Additional info

No response