Thats right, I also noticed that.
To fix, it’s as easy as changing line 101 of panda/src/grutil/heightfieldTesselator.cxx from:
return lerpyh * yoffs + lerpyl * (1.0 - yoffs);to:
return _vertical_scale * (lerpyh * yoffs + lerpyl * (1.0 - yoffs));