NEF files saved on an external drive do not have their IPTC data with them when opening in Photoshop. If I move the very same NEF files to my laptop, then Photoshop reads the IPTC data.

Hi. I have NEF files and their .XMP files saved on both my laptop and an external hard drive. When the NEF files are opened from the laptop they keep their IPTC data. When the very same NEF files are opened from the external drive, the IPTC is gone. 
Also, Photoshop routinely goes into the spinning beach ball of death if I’ve been saving files through the Export>Save for Web command.

The laptop is an Apple M3 Max.
The hard drive is a 12TB Novus connecticut via USB-c.
The camera is a Nikon Z9.
Photoshop is version 27.11.0.