Unity4.6.1&Google Play Plugin//Freeze Problem On Quit Application On Android

I am using unity 4.6.1(Latest one) with google Admob plugin and google play services plugin(I use only login/logout feature of the plugin for now) .The problem is the following. When I run my game on android and play return button, game freezes for around 10 seconds and then exit. However, when I disable login/logout, it exits as it should be. Some guys on forums talks about Admob for this problem, but Admob is so good so far and seems not causing this. The problem seems to be caused by login/logout. Any help?

edit: When you never login in the game, the freeze problem doesnt appear. However, once you logged in and then logged out, it freezes on exit.

No one? Guys I need a solution. Any idea about topic?