Can't enter Champion Selection?

Hey. I had this annoying issue occur to me twice within the past month. I enter a queue to get into a game, and everyone accept the match. Then I am supposed to switch to the Champion Selection page, right? Nope. I can hear the music of the Champion Selection page, but I'm still at the start/default page of the client. One time this occurred when I was playing with friends, and they said they were in the Champion Selection and everything was normal while I'm sent back to the start page. Then the match was cancelled because I failed to chose a champ.

Anyone else had this problem? I imagine this being a larger issue to people who play ranked and they receive penalties for something not their fault (I got a 5 minute wait or something).