Yesterday I took some shots of my garden. Afterwards I wanted to check them and edit them and: they were gone, not on the card, nothing, no pixels, nada! The last shots recorded to the card I had taken 24 hours earlier and the was no sign of malfunction AT ALL. I put the same XQD back into the same camera and took more shots: Everything was fine. I put another XQD into the camera today: all fine. Well that is a reason to go back to chimping, which I usually do not do with the D500 & D850 because these seemed so reliable. Till yesterday.