Summoners Rift Béta bugs

I noticed a bug where champions that go in stealth will not directly be revealed while in turret range.

Another common bug is that a random player crashed or even can't get in the game add all. In the last 20 games their was always someone in the game that dc & when afk on a certain moment in the game. Ok I can understand that the game can be buggy. But 20 games in a row... I even start to doubt it's an actual bug. Are they are doing it intentionaly or what...