I've discovered this applies for both threads (core XF) and also Resource Manager. My initial find was in Resource Manager as when I intend to upgrade addons, I tag what I need and then work from the list in my bookmarks. I'm lazy enough not to remove the old tags most of the time, but it was...
I've given a user the permission to edit posts by self.
I've used the analyze permissions utility to make sure the permission for that user has a positive value. Yes, it does.
As a final step, I've used the test permissions utility. Unfortunately, it does not show the edit link in the footer...