Under 12 my empeg would remember the last source it was playing in the car when it was returned to the car. i.e. tuner on: turn car off: power up at work no tuner: power off return to car: source is player not tuner.
That sounds like the correct behavior. What's it doing instead of that?
EDIT: Wait, you said "last source it was playing in the car", which is not correct.
The correct behavior is: If you take it inside, and it switched to "Player", then the next place you plug it in, it should be "Player", not tuner.
I don't think it EVER would go back to tuner if it was on "Player" in the house, even in beta 12. The only time it would stay on Tuner is if you pulled it out of the dash as "Tuner", it sat there not being plugged in, then you put it back into the dash and turned on the ignition. Only then would it go back to Tuner.