I had this happen on my 2nd Breeze. In a stable hover, then it started rotating, not real fast, but I was not doing it. I was about 4' off the ground. The GPS held it's position fine, I landed, and took that Breeze back to Walmart and got a new one. No questions ask. I have had 2 other Breezes with various issues, but only one with that problem. (The one I have not seems to work perfect, flying in the same location, and many other locations). I did the preflight calibration, there was no metal of any kind around - and I was too new to Drones to determine what the problem might be. As I recall, it did not happen every flight, and I flew in the same location each time - front yard, over grass.
Proceed slowly, do some testing - take off in a different spot, make sure the IRS can get a good initial fix (meaning there is a level surface and it's about 1" off the ground). By all means, stay below 6' for a while until you determine there is a problem or not.
Good luck.