Miande did you ever get this issue fully resolved? If you look at my post history i had the same problem stemming from 2021 when I picked up my 1835m hydro. I suspect it might be either a pedal position sensor or an issue with the electronic dial controls for speed and response. (Two dials near the cruise control button). I have around 170 hrs and have just lived with the problem for now. Like yours the problem usually shows up after the unit is warm.