mastery bug

This has happened to me twice now in about a 2 week period. i am using the new client. after selecting my champion the game lets me start changing my masteries. then it just stops letting me pick anymore. the first time it only let me put 12 points into a tree and the 2nd time it was 18, but when i got into game i had no masteries. it wouldnt let me change/pick/select anymore masteries or a different mastery page. 1 was in a normal game, the 2nd was in a ranked game.