Photo Looks Correct but Develop Settings are set to default

Hi Community.  I have an unusual issue I've never seen before.  I imported photos into Lightroom.  In the development tab, I made several changes, B&W, Exposure, Highlights, Shadows, Clarity etc.  So I made several changes.  During my session, I copied the Develop Settings and Pasted them to other photos in the same catalogue.  This all worked as expected and all was good.
A day later, I took a few more photos and imported these extra photos into the same catalogue by Synchrozing the Folder again.

The Issue:
The photos that I had made changes to, still look correct with all the changes applied to them, however, in the develop menu all the sliders are set to default, as if I hadn't changed them at all.
I only discovered this problem when I was copying and pasting the settings again and realized the photo wasn't changing.

Has anyone seen this issue before?  I've restarted Lightroom, I've reset the preferences but to no avail.

Any and all help would be very much appreciated.

Windows
Lightroom Classic 11.5