Bug 1863817 Comment 2 Edit History
Note: The actual edited comment in the bug view page will always show the original commenter’s name and original timestamp.
Fixed by the following addition in bug 1862973: https://searchfox.org/comm-central/rev/2b5fa337801646b75106595af329cc36943ae37d/mail/themes/osx/mail/contextMenu.css#38-42