I flew the P4 with the update today at a low altitude and it now follows the terrain. I flew it over a 20 foot drop and the P4 dropped. Maybe it did this before and I was just flying too high to notice. Normally I try to fly at 100 to 150 feet to get above the trees. Today I was about 20 feet up as I wanted a different look at a trail construction site. No workers today as it is Sunday.
At 20ft you would have been using VPS for altitude. When you flew it over the drop it lost VPS ability and switched to barometer and that may have had a different estimate of altitude and so it corrected itself?