[Beta Client] Unable to select masteries during champ select

I have had this problem during alpha and now beta as well. I am unable to select my masteries during champ select. Usually I can select the first mastery but after that none of the other masteries are ever selected. I select a mastery and it somehow is just unselected. I thought maybe I am just lagging and I am unselecting the mastery myself but I have tried doing it slowly and giving the client time to register my clicks. This doesn't happen all the time but it has happened to me ~10 times now.