We are experiencing the same issue with one of our ROVs, Navigator and Pi4, non-heavy config, latest stable Ardusub FW and latest beta BlueOS.
It is also combined with something similar to this thread - Pitch/Roll drift
Tried parameter reset and recalibration, can’t see anything weird in the logs. In manual mode all normal, but in stabilise mode seems sluggish and in depth-hold we have roll drift and super rapid random ascent or descent on forward or aft movements.
Hoping for a fix soon.