I had the same warning yesterday while test flying after installing newest update. While flying in "Sport" mode, I let off the throttle abruptly....and up popped the warning. AC hovered...hit mode switch to atti and back to "P" mode....warning went away and regained control of AC. This is the first time I have seen such a warning like this ever! I think it has something to do with the abrupt and sudden stop(braking) of the AC?