I can record fine with front camera with Mimo, in iPhone app front and rear and in Filmic front and back but not the rear-facing camera in mimo. It shows recording but when I go to look for video its not there. Not in iPhone native app either. I am also having an issue with the level. Perfectly balanced and calibrated but continues to stay slightly off level. Any help would be much appreciated.

Just to be sure, do you mean footage isn’t being recorded when using the dual cameras on the back of the iphone (not the front selfie camera)?  I use an iPhone X and iPhone 7. I haven’t had any issues recording with the rear camera. The footage is stored in the standard location within the photos app.

But, like yours, my om3 also suffer a horizontal tilt issue. Whether using a 7 or X (both perfectly balanced) when in video mode (with follow me mode selected) if I pan left or right the phone will not be perfectly level by the end of the gentle movement. Footage can sometimes start with the horizon not level too. But if I use the m button to switch modes to Photography the gimbal will immediately correct the horizontal tilt. Does yours do the same?