I have had 3 occasions where the drone wants to fly away.  It happens when flying with video recording.  The number of satellites drops from 6 to 4 and the bird becomes unstable and flies in uncontrolled fashion.  The GPS system is a problem  First, it will only find 6 satellites when my phone based satellite checker shows 11 are available.  Second, the loss of just one satellite connection makes the brid lose GPS stable flight.  What is wrong?

there are a few tips on youtube on this..

take the top off, re-route the gps lead under the covering in the lid.refit wire to the quad  ,retighten the screws and test.

i have just donr this with mine. went to the park today and was getting between 7-9 sats with gps lock, switched on the camera for vid record and , bamm, 3-4 sat loss..ATTI mode kicks in, turn it off again and back to 7-9 sats.

had a ground test in my garden tonight, had 4 sats before..now 7 solid sats and even when i click on the video record.

search youtube , you will find it

Send it back to Dji and they will fix it  they have fitted extra stuff to the newest version so dont mess about  get them to fix it for free.

If the Phantom in Atti mode (when less than 6 sats locked) is unstable and flies in a uncontrolled fashion then there is something wrong with it.
Atti mode is very stable in normal flying conditions. You will have to correct for drift if its being blown by the wind, but apart from that it should respond to all controls normally.
My V+ always has good GPS, but I still switch to Atti for most of my flights as its good practice to learn how to control the Phantom.