I once had a dark stripe at the bottom of an image when using a Profoto AirRemote/D4 pack at the 1/250 sync speed with the XT-2. I continued shooting at 1/125 to be on the safe side (it was a darkened studio, so no problem). Towards the end, I switched the camera and the trigger off and on and it didn't occur again. My takeaway is to use 1/125 where it doesn't matter (studio @ f8-11) and keep checking my frames from time to time when I need the higher sync speed (outside and/or open aperture).
