Lock a champion Ban Bug

Hello, my boyfriend is having some issues with champion select in ranked mode for 2 days now. Whenever we attempt to play, randomly he will get a ban for not locking in a champion, despite the fact that he did. He locks the champion, and despite that the countdown keeps counting down, and then he gets a ban. This doesn't happen all the time, but so far it has happened three times. The bans have gone up to half an hour now, and it has turned gaming quite a trip. Has anyone else experienced this before? And if so what can we do to fix this bug? Thanks in advance guys :D