Hey kkpiehl,
We're grateful that you posted here so we can help you figure this out.
For this issue, we want to recommend that you try the following steps to see if they might get things working again for your Shared Albums:
On any iOS devices you might be using:
- Navigate to Settings > [Your Name] > iCloud > Photos and toggle Shared Albums off.
- Leave Shared Albums toggled off for 10 minutes.
- Restart the device: Restart your iPhone - Apple Support
- Go back to Settings > [Your Name] > iCloud > Photos and toggle Shared Albums on again.
On your Mac:
- Open the Photos app and click Preferences > iCloud and turn Shared Albums off.
- Leave Shared Albums toggled off for 10 minutes
- Restart your Mac: Shut down or restart your Mac - Apple Support
- In Photos, pull up Preferences > iCloud again and toggle Shared Albums back to on.
After those steps have been completed, wait a few more minutes for the content to load in before testing to see if this issue is resolved. Please note that it may take up to 24 hours for those photos to finish syncing.
If the issue continues to occur after 24 hours, go ahead and reach out to Apple directly. If support is available in your region, this will let you work directly with an AppleCare Advisor who specializes in resolving this exact type of issue. You can begin by reaching out here: Get Support
We hope this information is helpful!
Have a great day.