Just looked now, and I had an outstanding request from a friend to help them with a goal. I looked at it, and I now have the option to join that friend and help them, or join a random group.

So it seems that might be fixed now.

Of course, joining an invited goal allowed me to go over the 10 goal limit .. don't know if that's intentional - I can't join another goal as it tells me I'm at the limit, but I wonder if I'm invited to another if I'd be able to join that.