You can delete this thread, as I'm finding out there's more to it. My "Co-admin" seems to know a little bit more about the situation behind the issue, and the issue might stem from another problem, which might have a correlation to posts made by users on a private board which oddly enough I can see, even though I'm not assigned to the rank that would allow me to view it.
If I can, when I find out what it is, I will let you know. Right now, it doesn't seem to be what I described, as I believe now, what seemed to happen like clockwork on the activity feed, was done at will by particular users exploiting some bug.
Edit: From what I was told so far by the other admin, they would make a post in their private forum, logout, and everyone but them would have posts disappear from the feed.