You have to actually enter the ga. Joining and seeing feats is not actually joining the ga.
It's pretty dumb the way they have it set up. For example why would anyone NOT want to join week 2 or 3 especially after competing in week 1, it should automatically join you into matchmaking.
At a minimum there should be a auto join ga setting somewhere.
Currently you have to click on the enter button behind a join button behind the ga icon essentially hidden 3 screens deep and if you only go to ga screen and only hit join then stop you only did 2 of the 3 steps.
