Very weird, and I can't find anything about it on the blizz forums. But since this morning, I don't get the authenticator request window. It just logs in straight after I typed my password.
When I log on to battle.net site it still asks me for the code, and it still shows my authenticator attached. My first fear was: help I'm hacked again, but since nothing is missing, and all is looking normal.. is it a bug of some sort?