My new XF 10/24mm lens when fitted to my XT3 has an intermittent problem. When in portrait mode (and only portrait when the hand grip is uppermost, not grip downmost) the focus is jerky in manual. If I turn the focus ring clockwise the focus distance indicator will not move, then move towards the infinity end of the bar, then maybe stutter and jump backwards a bit, then jerk towards the infinity end again. Ultimately it gets there but it staggers like a drunk. The happens whether focusing in or out, and is not consistent, it is quite random. In auto focus it's fine. In landscape orientation and portrait grip downmost it's fine. The issue starts about half way between landscape and portrait (grip uppermost).
I have tried with OIS on and off, no difference. I have two other lenses and both are fine.
So the lens went back to Fuji under warranty. They stripped the lens, adjusted it,and said all is good.
When I received the repaired lens it had the same problem. So I borrowed a different 10-24 from the camera shop and that lens worked fine. So, I thought the problem was definitely my lens. But I then tried by lens on an XT4 (no XT3 available in the shop) and it worked fine on the XT4. So I am now thinking maybe it's a combo problem of my XT3 and my lens. I checked and the firmware is up to date in both camera and lens.
In a final attempt to fix the problem the camera shop reset my camera. At first I thought this had fixed the problem, but it hasn't.
Before I send my camera/lens combo to Fuji I thought I'd check if anyone else had come across this problem. Thanks.