error when deleting a user from a recurring event

Steps to reproduce

1.Create a recurring event and invite a user to all the events. the user accepts
2. in the second event (or any other event except for the first one), delete the invited user
3. save the change to all events

Expected behavior

the user gets deleted from the event of which he was deleted from and all the events that come afterwards

Actual behavior

an error hapens that the event cannot be saved, and in the developer tools you can see that there was an 412 (precondition) error.

!Note.
i tested this again, and it seems the error hapens when the attendee accepts the invite and i remove him before it refreshes on my side.

Calendar app version

6.5.0

CalDAV-clients used

No response

Browser

No response

Client operating system

No response

Server operating system

No response

Web server

Apache

Database engine version

None

PHP engine version

None

Nextcloud version

No response

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

this is the error i see in Nextcloud

this is the error i see in the dev tools

Start in the Calendar app's recurring-event attendee deletion flow and reproduce the reported steps: accept the invite, remove the attendee from a later event, and save changes to all events. Use the browser developer tools to inspect the 412 precondition response and compare behavior before and after the attendee acceptance refresh. Done means the attendee is removed from the selected event and all following events without a save error.