I have a dark & cold cockpit situation, which also sets avionics to off. Now when I power up the plane, it seems as if the avionics are not properly turned on by the VC avionics master switch: the HSI won't properly align. Only when I use a keyboard shortcut for avionics, and hit it twice, the HSI aligns properly. Maybe this is the reason for your problem too?
Regards,
Juergen