This might be strictly related to the Phabricator dev instance, but not for the production instance? Not sure
Bug 1599815 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.
This might be strictly related to the Phabricator dev instance, but not for the production instance? Not sure, but I don't want to spam the production instance with test patches