This might be related to the variable idle RPM. Is there a behavioural difference between a cold and a warm engine?
I started with the engine cold, but on an Warm ambient temperature. I tried to heat the engine up by driving on the rollers with brakes on. With the cold engine, no creep, but when the engine warmed up to about 55° the creep returned, although not really smooth. Overall the idle is jerky, and so is the creep in extension. Tested today the engine warmth thing