Error Downloading / One Way Sync

Hi,

I would appreciate any help on a very frustrating issue.

I have an iMac with Photos set to iCloud sync and download originals set and an iPad, both running latest OS.

When I edit one of 50 photos on the iMac I get the white cloud symbol stating 'Error Downloading original'. However, I am able to edit the photo and if I go to Power Photos I can see the path to both original and edited photo and both photos open in Finder no problem. However, the edits including moving to an album do not get sync'd to the iPad.

However, the photo does exist on the iPad and if I edit it, the changes are being sync'd to the iMac and the error message goes away. But if I try editing the photo on the iMac again then I get the error message back and the edit doesn't sync.

So basically, the sync is only working one way and when I edit the photo on the iMac it triggers a 'Error downloading original message'.

Oh and I've tried exporting both the original and edited photo from iMac and that works fine, but I can't duplicate it.

So I've tried all the usual tricks to fix the sync issue but no luck so far.

I know I could probably just export them, delete them and reimport but I would lose the Live Photo and that doesn't fix the problem.

Thanks

Russ