Adding an attendee to a recurring series with a moved occurrence - moved instance is invisible to the attendee, and shows no attendees to the organizer

Steps to reproduce

1. As organizer, create a recurring event in the web UI: daily, 4 occurrences, no attendees. Save.
2. Open occurrence NR-2 in the editor, change its start time (e.g. push it by one hour), choose Update this occurrence.
3. Reopen occurrence NR-1 in the editor, add one attendee (another local Nextcloud user), choose Update this and all future.
4. As the newly added attendee, look at the series in the calendar.
5. As the organizer, reopen the moved occurrence (NR-2).

Expected behavior

• The newly added attendee sees the series in the same state the organizer has, including the moved occurrence NR-2 at its new time.
• The organizer's moved occurrence NR-2 lists the newly added attendee - "Update this and all future" was applied to the whole series.

Actual behavior

• Symptom A - attendee side: The new attendee sees the series at the original times. The moved occurrence NR-2 appears at its original time, as if step 2 had never happened.
• Symptom B - organizer side: When the organizer reopens the moved occurrence NR-2, the attendee list is empty for that occurrence. The series master (occurrence NR-1, NR-3, NR-4) shows the attendee correctly.

Calendar app version

6.4.2

CalDAV-clients used

Browser

Chromium 148 and Firefox 151

Client operating system

Manjaro Linux

Server operating system

Ubuntu Linux

Web server

Apache

Database engine version

MySQL

PHP engine version

PHP 8.3

Nextcloud version

33.0.3.2 - also reproduced on 33.0.5 (current latest Docker image, "Nextcloud Hub 26 Winter").

Updated from an older installed version or fresh install

Fresh install

List of activated apps

Nextcloud configuration

Web server error log

Log file

Browser log

Additional info

Reproduce the four-occurrence scenario in the issue using the Nextcloud Calendar web UI, checking both the attendee's series and the organizer's moved occurrence. Done means the attendee sees the moved occurrence at its new time and the organizer sees the added attendee on that occurrence.