I am running into the same issue. I think I’ve narrowed it down to the zoom ring. I manually move the zoom ring a few times back and forth fully and the issue fixes itself. I’ve yet to have this happen while filming…in other words…it happens when I turn on the camera. But once I fix it…I don’t have the problem come back until I turn off the camera. Since I’m a wedding videographer and leave my camera on a lot, and have plenty of batteries to do so, and can fix the issue quickly and consistently, I’ve decided to not send the lens in for repair…at least that is my current plan