https://bugzilla.mozilla.org/show_bug.cgi?id=1576567#c5 may be related.
Bug 1929107 Comment 1 Edit History
Note: The actual edited comment in the bug view page will always show the original commenter’s name and original timestamp.
https://bugzilla.mozilla.org/show_bug.cgi?id=1576567#c5 may be related. Edit: and bug 1522394 (User story point 2)