I was shooting at football yesterday and noticed that the lens mount felt loose, with the 70-200mm on the camera, carried on shooting as I had no alternative with me, and in a couple of frames there was a definite alignment issue. As you can see in the image below, muzzy top right and bottom left.
Got home later that day & checked, and all four of the lens mount screws were loose, not just a little bit loose either. I usually remove and reinstall them with some thread-lock when I buy the lens, but I appear to have missed this lens. So tightened them all back up & then thread-locked each one in turn. Whilst was at it I checked all of my other glass, without finding a problem, which is good news, as they are all transported and used in the same manner.
SO if you haven’t recently checked any screws that you can access are done up correctly, now is the time to do it.