I've been searching around and can't seem to find a fix. My horizon is tilted so the left side is slightly lower. It's pretty minor and has been present in several of my videos, although I just noticed it tonight. I've found several other people complaining of the same thing although I haven't seen any fixes. I've tried an advanced IMU calibration and I will test it in the morning. However, I have done calibrations in the past and the tilt is present in past videos.