I received your NEF file from weTransfer. I copied it to one of my XQD cards. I imported it via USB3 and again via USB-C. Each time I was able to see the thumbnail preview. It is possible that the copied file behaves differently from the original file laid down on your XQD card. And for this reason you also do not see a problem if you copy the card contents to a local disk drive.
In your email, you indicated that resetting the preferences file did not make any difference. In composing this reply I have questions about the formatting of your XQD card. how often do you reformat the camera card? Do you use the camera to reformat (preferred) or have you reformatted the card using the Disk Utility? if you use the camera to reformat, try reformatting with the Disk Utility or vice versa. Let me know if there is any difference in thumbnails with the different reformat.
With this information, I think your next step needs to be reporting it to Adobe via the
feedback site. This was a suggestion from Jim Wilde. Be sure to mention that another person (you may use my name) also has successfully used the same equipment (both USB3 and USB-C) to import NEFs without problems.