I think the joystick input was causing some of the issues last time, but I've been more methodical in testing this time, and still seeing some issues.
I couldn't get it to drop to 20 altitude like last time, but there was some other strange behaviour.
When I engaged Stable Hover, the altitude increased uncontrollably.
I've uploaded a video, and in the description I've added the steps I took. This was in Free Flight, on Task Force Lebanon map.https://youtu.be/EwEvshJp9u8