(New Client) Mastery page missing a chunk?

This has happened to me four times now, I pick my champ then try and set my masteries, and about 1/5 of the client just disappears. Its not just that I cant do my masteries, I also cant close the page. So if I start setting up my masteries before I lock in, I get leaver buster for not banning or locking in. The part of the client that dissapears seems to be the Friends list bar.