[@_ck_ Participant 18 years, 3 months ago]

Update: I found the problem. It’s the same one I reported here:

https://trac.bbpress.org/ticket/704

If a forum page has sub-forums visible, it messes up any function that depends on calculating the current forum_id. It will instead return the last sub-forum’s id.

So the pagination didn’t think there was anything to paginate.

Should be interesting to see how they fix that.