Dynamic Wallpapers not changing gradually?

Give this a try: boot into Safe Mode according to Start up your Mac in safe mode - Apple Support and test to see if the problem persists. Reboot normally and test again.

NOTE: Safe Mode boot can take up to nearly twice as long as a normal boot as it's doing the following; 

• Verifies your startup disk and attempts to repair directory issues, if needed

• Loads only required kernel extensions (prevents 3rd party kernel/extensions from loading)

• Prevents Startup Items and Login Items from opening automatically

• Disables user-installed fonts 

• Deletes font caches, kernel cache, and other system cache files

Hi mkalc,

Thanks for the additional information! Were you able to test the issue with a different dynamic desktop picture to see if it's behaving the same way as your current one? If not, we'd recommend testing it next to see if the issue could exists with multiple dynamic desktop pictures.

We'd also recommend ensuring that your Mac is up-to-date with the latest software by following the steps in How to update the software on your Mac.

Let us know how this works out for you! Be well.

Hi mkalc,

Welcome to the Apple Support Communities and thanks for posting your issue here! We'd be glad to help check this out with you. We understand that you're having an issue with your dynamic desktop picture working properly. When you have this dynamic desktop picture selected, do you notice if the color would change only once throughout the day? When you mentioned that the color would change abruptly, are you only seeing the same two shades of blue and orange each time? Have you tried another dynamic desktop picture to see if it's having the same issue?

To make sure you're not missing anything, we'd recommend reviewing the information in Customize the desktop picture on your Mac.

Cheers.