Terrain following works perfectly with my plane (using Pixhawk) and I always check the altitude in right-click Map Tools/ Elevation Graph to make sure I haven’t made an error setting the altitude at each waypoint.
After upgrading to 1.3.51 this didn’t work at all and showed my altitude above and below the ground in a seemingly random altitude pattern.
I made a new simple 10 waypoint route all 50m above ground in terrain follow mode and the same thing - sometimes it showed my altitude below ground and sometimes above at random altitudes instead of a contant 50m above ground level.
I deleted 1.3.51 and reloaded 1.3.50 and this was back to normal and working fine.
Is it a bug?