Found a bug in assembla ticket comments section

Let me explain by an example. 

Let person B replies to a comment of person A on a ticket. Now person A should reply in another comment that would appear below the comment of person B, but there is also an option of editing a comment. So person A can also edit his older comment in reply to comment of person B which is ethically wrong as he should have added a new comment in reply. Buta notification should appear on the ticket as ' Person  A modified his comment ......' which is a bug that it doesnot appear. The ticket would show like person B made a wrong comment but he had not .