I had a chance to fly today as the winds were calm and not 25 gusting to 35 miles per hour as predicted. There was some strange behavior in the heading hold gyro and I was wondering if it was due to the cold. The helicopter was in a 70° basement and I brought it outside to 35°. As I flew, I noticed I needed to add left nose trim about every 2 minutes. At the beginning of the flight the trim was about a click to the right of center, but at the end of the flight it was between center and full left. Once I landed I added full left trim to stop the tail motor. Even at full left trim the motor would run if the helicopter was rotated nose left even slightly.
I’ve heard that the gyro can cold soak and cause drifting. Anyone here experience the same behavior? Is it always to the left? Do belt driven heli's experience the same problem?

AXE CP
G90 gyro
Outrunner tail motor and 4530 prop