BuddyPress.org

It took me awhile to think about what might be causing the issue and I just remembered the problem.

It’s a theme conflict with BuddyPress.

BuddyPress adds the CSS class hidden to a group in the group loop. Some themes might already have a .hidden class declared, so hidden groups are not shown because of this.

Can you add the following CSS snippet to your CSS?

#buddypress .bp-single-group.hidden {display:block;}

I believe this should fix your problem.