It sounds like you aren't actually engaging Hover-Hold or Stable-Hover-Hold. If you are dropping down to 20m, it stops because of the ground effect, you are not actually hovering. There is a complication to engaging the Hover modes in the Razorworks code. You have to be below the speed limit of (now) 40 knots AND you have to let go of the joystick... It has to be centered. I found that part in the code when I went in to edit it. I forget to let go of the joystick every once in awhile myself. It's pretty annoying if you don't know it's in there. I don't think it's even mentioned in the manual either.
I checked, and it's not in the manual. There is a warning for being over 40 knots, but it doesn't sound because the recording is blank. There isn't a warning if you don't center the joystick, it just doesn't engage. Annoying as hell. It might be in there because any offset of the joystick disengages Hover mode. I'll test it tonight, but I don't think I can take it out without breaking it.