Yeah, possible. Or the PF may have accidentally raised the gate release triggers. Only one of them needs to be lifted 2mm for both power levers to come back from flight idle!
I had heard this theory before and thought it sounded very strange. So, yesterday, while on the ground with engines off, I tried it and proved that this is NOT so. For BOTH power levers to be brought aft of the flight idle gate, BOTH triggers have to be lifted. I tried it on two different aircraft and had the same result. Lifting any one trigger will not cause both levers to move. Whether or not this magically changes inflight, well I'm not brave enough to find out.
EDIT: This was done on Dash 8 300's in case anyone was wondering.