Sync - 100%: 98%?

Hi Folks, first post here - looking to master a quick backup of my device before I send it back to to shop due to fault.

I’m doing a one way ‘sync’ - one device tells me 98% and good; the other tells me 100% and bad…

I followed through the thread here and Settings > Troubleshooting > Reset Delta Indexes on both devices, but no change other than 98%/good device no longer shows 676/676 files.

Here’s some pics to tell a thousand words:

Thx M