I have a problem that left rail / rudder and right rudder behave different. Which means same stick inputs give different rotation speeds. For example having -20% on the rudder, and +20% results in different rotation rates.

The heli is Goblin 570 Sport, running on Spirit Pro.
My first thought is heli cannot reach desired rudder rotation rate at one of the sides, but then I found it also happens at low rudder speeds.

I test it with SimMatch (http://rc.a-soft.org/?page_id=68) which I trust, as I wrote it. But I can run some more tests in the field if needed.

Is this maybe some misconfiguration of Spirit on my side? Which parameters can affect this?