Won't let me select champion

This is the third time this has occurred to me so I figured I would report it. The game client itself seems to have a memory leak as it gets increasingly laggy the longer it is open. The particular issue I have had is during champion selection when you are required to ban or select a champion it will let me select a champion, but the button "lock in" or "ban" won't ungrey... so I can't select or ban a champion. Then I will get booted and it will stop me from playing for 5 + mins. I'm legit just spamming lock in for the 30 seconds that its counting down until I get booted. Can you please look into this negative play experience?