Rizer calibration variation problem

[pierre.lepeer]

Hello everyone,

I don't know if this is the right place to ask, but I have a Rizer with which I encounter a curious phenomenon, at least on Zwift:
I calibrate it to have the handlebars straight before riding, but as I ride, little by little, I deviate more and more to the left, which I gradually have to compensate for by initially turning slightly to the right to ride straight, but after two hours, I'm almost with the handlebars at maximum right. If I calibrate it again while riding, everything returns to normal at first, but the phenomenon returns.

What could be the reason (and the solution)