[UPDATE 17th of July, 2016]: Nikon meanwhile published a firmware update that switches off UHS-II and reverts to UHS-I in case the camera determines a problem. UHS-II will be re-enabled after the standby timer shuts off the metering system. Nikon admits that errors can still occur, but very rarely. This is a workaround rather than a fix. Most surprising is, that Nikon argues that the error lies on the card side of the equation. This would imply that almost all vendors have problems with UHS-II cards. Very unlikely.
Currently the web discusses intensively the compatibility issues with Lexar UHS-II SD cards of the newest 1000x and 2000x speed ratings. During playback the D500 reports suddenly that the SD card is damaged and cannot be used.
Those issues do not seem to be isolated to the mentioned Lexar cards. Within the first test shots with a newly arrived D500, I received the error with a Transcend 64 GB UHS-II DS card with 180 MB/s write speed rating.
In my opinion Nikon seems to have a general issue with UHS-II cards in the D500. Despite the fact that no issues with Sandisk cards are reported so far, the problem might be more on the side of the camera than on the side of the SD cards.
To utilize the full speed of the camera, the only choice currently is to use a XQD card without backup. Purchase of additional UHS-II SD cards should be placed on hold for now, at least until the issue is acknowledged and sorted out.
Nikon has to react quickly with a firmware update or at least with the announcement of such. The fact that several owners of the D500 discovered the issue quickly within the first pictures taken raises the question, what and how deep Nikon is actually testing its new products before launch.
[UPDATE 10th of May, 2016]: Taping off the additional UHS-II contacts on the Transcend card cures the problem. During more than 500 pictures the issue did not come up again.