Undecided if anybody else has the IBIS concern, but it surely’s on BOTH my cameras after the firmware. Utilizing the RF 70-200 or 100-500 at longer focal size the IBIS will “stroll” once you maintain the shutter down. It’s at all times down and to the suitable. Finest option to describe it’s that the picture body begins to maneuver right down to the suitable as you maintain down the shutter button. It then corrects itself once you launch it. Occurs randomly and I lastly have some downtime to ship one of many our bodies in with the 100-500. Hopefully there might be a solution.