Calendar fails to display tasks with due dates with a red error message

### What Happened?

I removed my CalDav online account and re-added it.
When I opened Calendar again, it displayed an error message:

Unable to connect to “TLE Tasks": Backend factory for source *b458ba0756188af7f450b3924884eff423ecedff” and extension “Calendar” cannot be found.


If I uncheck the tasks lists in the Calendars list in Calendar, the error disappears.

Note: if the tasks lists are checked (supposedly visible), the Date and time indicators crashes the whole top panel when opened.

### Steps to Reproduce

1. REmoved my CalDav online account (nextcloud)
2. Added it again with URL, Login and app password
3. Login works and list of calendars appears, including the tasks lists
4. Open Calendar
5. The banner appears

### Expected Behavior

There shouldn't be an error message, and the tasks with due dates should display in the calendar, as well as in the date and time indicator.

### OS Version

6.x (Odin)

### Software Version

Latest release (I have run all updates)

### Log Output

_No response_

### Hardware Info

Mesa drivers (integrated AMD graphics from a ryzen 4800H).
Nothing special in the setup
THe caldav calendars and tasks lists are provided through my own Nextcloud server, using https
The "Tasks" app manages to open the tasks lists and interact with the without any issue.