I have found (in the Edit Accidental dialog) that if I duplicate an item, work on it a bit and then change my mind and Cancel, the new item is still there in the list. I might then try to delete the original, not realizing there are now two. So it seemed as if Deleting did not work, when in fact it was Cancelling that didn’t do what I expected. I don’t know if this might explain your experience at all, but there it is.