Thanks for the report Alex, I can reproduce that on my machine. I am also seeing the following error message in the Browser Console
Bug 1571637 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.
Thanks for the report Alex, I can reproduce that on my machine. I am also seeing an error message in the Browser Console. Attached in case it's relevant. Honza