I just purchased a P4 Pro, V2, and went through all of the usual updates to the firmware / Go app, etc. and flew it a couple of times with no issue. Then, I had a message on the controller saying it need a firmware update, that didn't show up on the DJI assisant app, so I did that as well.  After the update, I had a hard time getting the remote to link with the P4.  After many tries, it finaaly linked up.  The controller said it was in GPS mode and the home piont had been saved, and I took off.  The P4P acted sluggish  - drifitng when I released the sticks, and would not hold altitude or postion well when in hover.  I went up about 50 feet, and then the drone became all but un-controllable, and I got a warning saying "navigation system failure - Check redundancy state".  I had a real fight to get it back on the ground, it kept pitching in different directions and was rising and falling.  I finally got it down, and re-ran the IMU and compass calibration.  It seemed to be OK after that, but next time I flew, same error.  It also keeps losing GPS signal, and the compass in the lower left of the screen is really "jittery'  This is a brand new drone, with about 30 minutes on it.  I have a P4, P4 pro - v2 and a mavic, and had a P3P, so I'm familiar with firmware and software updates.  I am using the crystal sky monitor, with the latest DJI Go app on it.   Any ideas on what may be causing the issues would be greatly appreciated

I am also facing exactly same problem in phantom 4 pro v2.