Spline Waypoints with LiDAR Sensor in Terrain Mode

I have a Lightware SF-11C mounted on a 700-class heli, everything works well when flying flight lines in terrain following mode, but when in the turns when using spline waypoints, the angular distance increases and the heli descends, then climbs after finishing the turn. Are there any parameters to take into account the bank angle in the turns? Maybe there’s just no way to do this with spline waypoints?

I don’t have a gimbal for the camera mount, so the LiDAR sensor is just mounted to the underside of the frame on a fixed mount.

I imagine fixed wings would have the same issue but much worse, does anyone know if they’ve found a way to compensate for this problem?