BuddyPress.org

Yes, I suspect the group template only has the current group initialised when you are on a single group page. So, only has one group to loop over. The same as being on a single post page vs. a category page in standard WordPress. We had a similar issue with the activity loop.

Try passing the full set of parameters to the groups loop, rather than either a subset or none.

Let us know if that fixes it.