Phantom 4 Pro inconsistent behavious

Congratulations on such an intuitive and useable product.  However, recently I have seen some real inconsistencies in flight behaviour.  One flight works flawlessly followed by another which is erratic.  Take off is from an identical, clear position and compass health is checked beforehand.  Flight 1 is perfect, FLight 2 exhibits steady "toilet-bowling".  After changing flight location, this same pattern repeated itself.  The images show the perfect flight, the toilet bowl flight (aborted obviously) and both overlaid.