Yearly, whole-day event is displayed with start- and endtime "00:00-00:00"

Hej,
I created a yearly, whole-day event – a public holiday, called "<strong>Reformationstag</strong>".

This year the entry is shown like this:


For 2021 it is shown like this:


I tried everything but I am not able to avoid the display of a not given and not set start- and endtime "00:00-00:00" as it is a whole-day event.

Thanks for your support.

EDIT: I just noticed – it happens again in 2027! =)


I deleted the event and created it again - it happens the same way again.