Does organic groups restrict access to node revisions as well as the nodes themselves?
I have a node page with a view of the revisions output in a block in the sidebar. OG restricts access to the node itself if the user doesn't belong to that node's group however they can see the revisions in the block.
I have tried creating my own OG permission but the organic groups permissions aren't usable in the view restriction. Not sure what else to try?