Apple has fixed it, works as intended on macOS 11.5 Beta.
Bug #FB8955055
ruzambo
Users receive reputation points by contributing quality content to the forums.
Posts include post and replies published on the forums.
Post authors can mark replies as Accepted to indicate successful solutions.
Apple Developer Forums admins can mark replies as Apple Recommended to indicate an approved solution
From
Tallinn, Estonia
Post
Replies
Boosts
Views
Activity
I've got a feedback reply from Apple asking to re-check it on macOS 11.4 GM. Can't check it there however the issue is definitely resolved on macOS 11.5 Beta.
Hopefully they will merge this fix later. It sucks that I had to re-do whole app without Lists...
Hello @Tylor,
It works as intended on iOS. It crashes on macOS. Did you try that on a macOS target?
Filed a bug report #FB8965816.
The crash remains if there are children in items and you delete the last item.
Exactly the same code works as intended on iOS.