NC28 events of newly subscribed public calendars are not shown

[escoand]

Steps to reproduce

1. add new external calendar (in my case https://www.feiertage-deutschland.de/kalender-download/ics/schulferien-sachsen.ics)
2. the calendar is added but no events appear, without any error

Import of the same ICS file is working without problems.

Expected behavior

events appear as with NC27

Actual behaviour

no events appear

Calendar app version

4.6.0

CalDAV-clients used

No response

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

28.0.0.11

Updated from an older installed version or fresh install

None

List of activated apps

No response

Nextcloud configuration

No response

Web server error log

No response

Log file

No response

Browser log

No response

Additional info

No response

[escoand]

Maybe a duplicate of #5628

[C8620]

I think it is not a duplicate.

#5628 is about events in subscribed calendars not showing in the dashboard widget, and this is about events not showing up in the main calendar app.

[miaulalala]

Duplicate of nextcloud/server#42143

We tracked it down to a change in the upstream lib.