It seems like the DEM building is causing this distortion and then the orthomosaic inherits the distortion because its generated from the DEM.
I've just been playing with a new DJI phantom professional. I shot around 233 photos following a more or less random pattern for testing purposes. The drone was manually controlled and I shot images manually as well.
I've tried using different coordinate systems but I guess its not dependant on that isn't it?
Why would the images be bad georeferrenced? I recall that the drone just detected 8 satellites so it might have wrong or innacurate GPS positions. Is the DEM building process using them in some way? I am pretty new to aerial imagery and GIS so I am a complete newbie
Manuel.