Champ select black screen

A few times this has happened to me; I go into champ select (Solo, group, what have you) and it makes the 'SCHWING!' sound that it does when the list of champs comes up... but the screen is black. I can still click on the Friends tab, or the Events tab to see game invites, friend requests, etc. but I cannot choose a champion or type. I am forced to dodge and I'm afraid this is going to result in my losing LP or even getting banned. Over something I have no control over! Can someone please look into why this might happen?