Yes, it's turned off. What this setting do?
It attempts to find the best (highest) resolution for your HDMI hardware. It's best to have it turned off and select custom resolution.
Yours is the only report so far of this problem on 2.0.4 firmware. It might happen if when Q10 Pro boots it detects that your TV isn't capable of resolution/color space mode. I would be looking at the cables and anything between Q10 Pro and TV (AVR, switches etc).
Try connecting Q10 Pro direct to TV using supplied cable, do you still get problem?
On another Forum an user have also reported this "switchback" bug with 2.0.4 fw. As it seamed to be fixed, and some other users reported as OK and no occurring of the resolution reset -since they've installed 2.0.4-, but it seams it still happening in some circumstances... He has checked his full chain, AVR, TV, but no sign of malfunction or improper settings...
Edit: And could you please ask HiMedia for the possibly cause (or causes) of this issue? So we at least could have a clue that what would be the root of the problem, and -maybe- could try to figure out some solutions by our selfes. THY!