Raw photo icon preview in finder is borked

I am running Sequoia 15.4 on a 2024 Macbook Pro:

Finder will not display an icon thumbnail for a Canon raw photo file (CR2) when only one file/photo has been selected. The icon preview is completely black.

However, when I select more than one file, the icon previews are present.

With one file/photo selected:

With one or more files/photos selected:

I have Canon Digital Photo Professional 4 installed to facilitate raw (CR2) support.

The fact that icon previews are showing for multiple files selected but not for a single file has me asking what the f*** over? This makes sorting my photos more difficult than it needs to be.

Before you ask, the files are stored on a QNAP NAS and have r/w perms for the user/owner (me). I copied the files to the local drive (~/tmp/raw-photo-bug) and the behavior was the same (black for 1, icon previews present for 1+).

This seems like a bug to me.

Thoughts anyone? I'm stumped.