I am unable to set Photos as screensaver on iMac

FWIW, I started to see this back with beta copies of macOS Sonoma, and it still occurs with the latest version of macOS Sequoia.

In my case, I had a number of Photo folders that, for example, store images of seasonal photos, i.e., Spring, Summer, etc. I would then want to rotate thru these images to change the wallpapers being displayed.

I can select any one of these folders; however, it doesn't "stick" and reverts back to the default macOS wallpapers.

The workaround that I found was to first select the Photos folder I wanted, and then, individually select each image in that folder with each selection showing up as the wallpaper on the macOS Desktop. After doing so, I reselected the "rotating" image and the wallpapers would change as expected.

I don't think this is the way it should work ... at least, I didn't need to do this prior to macOS Sonoma.