Hi, just wanted to say 'me too'. I bought an AT 3 over the weekend and this problem is happening for me as well. I winder if it could it be some function between the itunes host machine and the ATV 3 that needs to keep poling the host.
I am gonna try turning off as many options as possible and see if it happens.
Might also be of interest to turn my iMac that hosts iTunes off for an evening and see if it continues.