Thank you for your feedback Eric.
but this is not the problem I meant. The favorites are working fine in terms of adding and deleting places.
The problem for me is in the section “Guides”. There is a list named “My Places”. Which is fixed and can not be removed. (That might be per design) Also the 8 places that are in that list can not be removed. And it is those entries I want to delete.
I have tried your described steps anyway to see if it would make a difference. My favorites list is now empty, this works fine. And rebooting the phone doesn’t make a difference.
I have also tried to logout and login from my apple account and switch the cloud sync off and on. So far without any success.
An indication that things are not working the way they supposed to is the data of the places. Although they all still exist there is no picture and the location info is reduced to coordinates only. (See pic)