Relation field not updated correctly

On a website, I use custom fields (managed by some plugin ?? ) for my CPT.
One of the field is a relation field. So it links two cpt together.
Normally, if you edit directly one of the cpt, it will remove the link in the other linked cpt.
But, when using PublishPress Revisions, the link is not updated/removed in the liked cpt.
Any clue on why or how to get around that?
As we use the plugin to allow authors to edit their own post, an admin have to go over and edit the second post to remove the link.

As a site admin, even if I have the right to edit other’s posts, i’ve got the problem.