Recently my Phantom 2 started returning home unexpectidly mid flight.  The issue first occured around four flights ago and has persisted ever sense at shorter and shorter intervals.  The problem is occuring with both batteries fully charged, in different geographical areas, far away from any non-fly zones, and after firm ware updates to both the Phantom 2 and the Gopro Hero 4. On my last attempt, the issue occured after full satelite lock but before the Phantom 2 had even left the ground resulting in the Phantom 2 shooting upward in what I assume was an atempt to reach the height threshold for the return to home function.  I was able to catch it mid-air but am not sure what would have happened next had I not. What is driving me crazy is that nothing changed between when the Phantom 2 was working five flights ago and when the issue started occuring.  Additionally I am on location in New Zealand and if I can't get the problem fixed ASAP (as in this afternoon) I will be missing out on some incredible footage.  Any and all imidiate help will be greatly appreciated.  I will be troubleshooting all day.

First I suggest you to calibrate the compass.  
Then, you can donwload a software in http://www.dji.com/product/phantom-2-vision-plus/download   to check out whether the MaxHeight and MaxWidth has been modified.
Hope that helps.