That’s weird! By click on delete you mean a button has the delete action on your app or the delete button after you select record/records on that collection view in your database? I don’t see any issues with deleting records on my side! Check this post posted by Colin : Delete DB record doesn't delete - #4 by anon78309838
If after reloading the tab , after clearing your cache and still not work I suggest to Submit a Support Ticket!