I received my MB-D18 grip today and inserted an EN-EL18b battery to test the frame rate. Sure enough, it is 2 frames faster than the camera without the grip as advertised. While testing I started getting Crd Err messages on just the Lexar XQD card. I tried to format it in the camera but it gave an error and said to replace the XQD card. I formatted the card using my laptop and then the camera recognized it. I started shooting high speed again and the camera froze with the Crd Err message again which required formatting again on my laptop. I have been using this card without issues since getting the D850. Is it possible that the grip or EN-EL18b battery could be causing the issue with the card? I will change out the XQD card and see if the error presents itself again, but was just wondering if anyone had any thoughts.