Image folders show box containing?

When this collection was used in W11 all was well. I have started to navigate the collection on a Mac and there are some oddities. Old Bridge cameras, all jpeg format, are showing a question mark in a box when I navigate to the folder. This is the case in very many of the folders. If I hover, the status shows ‘waiting for metadata’. I have gone into Settings:

Advanced - Automatically import and export sidecars
Metadata - Clicked the Synchronise and Write under the Metadata tab.

I have explicitly selected a folder and asked for it to be indexed but nothing changes.

I now note that a P&S Lumix, which has folders containing Lumix raw and dng (the dng files were created on Windows by PL6) are also showing ?. My old Nikon and current Olympus image structures seem fine.

The images are on the local drive in the mac (nothing in the cloud - never has been) and are all present and correct when I navigate to the folders in Finder - the ones I checked all contain an image file plus xmp and for many of them, a dop.

Additional after checking - on my Windows laptop, the bridge cameras are all visible but note that a module is not available and they show a grey symbol top-right of the thumbnail. The Lumix images (dng and rw2) are also visible but they have a module so no little icon top-right.

Can anyone offer guidance please?


[Edit] Four times today, when exiting, PL6 has gone ‘not responding’ and I have had to Force Quit. It then runs up next time with no problems and the folder I was in, previously ?, now shows all images. There has been a couple of updates recently, one today, and I wonder if they have introduced the problem.