I’m having a similar issue with BP2.1 and WP4.1. The group pagination links aren’t working on either the front or back-end. They work fine for the member list, but not the groups.
On the front-end, the links seem to be pointing to the correct mlpage=#, but when clicked they do nothing.
On the back-end, the links work for page 2, but all the rest are all pointing to member_page=3.
I’ve disabled all plugins, switched to default WP themes, and used a couple different browsers and the problem exists in all cases. Is this a known issue?