Interesting. I had this problem with lap 6 after laps 1-5 overlayed ok. Resolved by rebooting iPhone and lap 6 now overlayed ok.

Using v15.0.3 Professional on iPhone4 mounted in an Optrix holder suspended below rollcage - so camera lens is at bottom edge of iPhone when mounted. Got a great video of racing at Brands Hatch last weekend and lap overlays are going on fine (not finished all yet). :P I want to upload raw video to Y...