Membership 2 Pro causes blank screens for everyone

We use a lot of user roles in our Membership system here, but we’ve recently started trying to wall of certain content for certain groups. What ended up happening was turning content protection on on any page caused users to see nothing (or to see the content protection error) even if they should have been allowed to see it (we had a “default” group set up). This bug didn’t affect me or any administrators.

The other strange thing is that, if the user were logged out, the system would present a login form that would tell the user their credentials were incorrect, even if they were definitely using the correct credentials to log in. (They were able to go to a different login form and log in just fine.)

I’m totally stumped as to what’s causing this bug to manifest itself, but it’s pretty important to us that we get it working so I’d love any help. I can verify that it manifests if there is ANY content protection on at all. Some users report blank pages, other users report seeing our content warnings.