I just want to be 100% sure you’re clear about edit grace periods, which would still apply even if there is a different user editing the post.
(Yes, if user A edits user B’s post, there is always a forced edit revision, but that doesn’t mean that if user A edits user B’s post 6 times in 60 seconds, there are 6 revisions and 6 notifications created. There will be only one revision and one notification, as you can see in the above screenshot.)
Are each of these edits more than 5 minutes apart?