My Phantom 4 Pro has been sitting for over two years without a flight so today I charged the batteries and took it for five flights just to make sure it still flew well and the batteries were good. On the last flight when I was coming in to land in P mode, it started drifting like it was in Atti mode. No worries, I like Atti mode. Before hand-catching it I switched back and forth from Atti mode to P mode a few times to see if it would regain P mode but without success. Granted, even two years ago I had the same issue of it suddenly drifting when in P mode and updating the firmware and calibrating the IMU did not fix the issue. Just to make sure all was set, I reupdated the firmware and calibrated the IMU before todays flights. So, I'm curious why this is happening. Can anyone provide insight? Here's a link to the aircraft .DAT file on dropbox: Phantom 4 Mystery Atti mode