I was reviewing the "First answers" queue when I was presented with this post (*): it is clearly not an answer, so I flagged it as NaN and then I also clicked on the "Delete" button on the right side of the page: I was shocked to see a pink popup appear with the text "You cannot delete this answer". Is this a bug? If not, what is the reason for this surprising behaviour?
(*) If you clicked on it and you didn't find anything meaningful, then it must have got deleted already and you have less than 10000 reputation, so you can't see deleted posts.