I've tried two pedals, and they both do the same thing.
Firstly please check the condition of the cables - they can be pinched when installing the heel rest.
Secondly you can check the condition of the potentiometers. If they were somehow not installed correctly from the factory (rotation starting from the wrong position), it may be possible to re-seat them. Also if the three screws are not tight, the rotation can also move out of alignment.
This short manual might help:
If there doesn't appear to be anything wrong with the pedal assembly, or you are not confident to perform this check of the potentiometers yourself, or you simply want more detailed advice, please create a support ticket through the My Products section of your Fanatec account, and the technical support department will happily assist you.
[Fanatec Community Manager]