I have to take your word for this since I have no control over the camera coordinate system as in Mapper. Matic is much more of a “Black Box Solution” than Mapper, and I am not sure that I like that as a Land Surveyor.
Since this is the behavior for other DJI drones in the past, this could definitely be the problem. I did check the elevation of one of the cameras in Matic vs. the same in Mapper and there was a 4.62-foot difference. I then computed the EGM96 and the Geoid 18 values and subtracted and came up with a distance of 4.61 feet. This would indicate that the EGM 96 value is being erroneously applied. I have never understood why you would apply a geoid value to the image. This was the first thing I advised clients to change in Mapper.