It seems you have synced your images to Lightroom mobile.
Some of the images have been synced. However, some of the images has not been synced due to errors.
Please follow the steps provided in the below link and check for the issue.
Let me know if this helps.
On Mac drop the /Users/intel/
Just start at Library
Library/Caches/Adobe/Lightroom/Sync Data/ and remove (or rename) the Sync.lrdata folder
I am having a similar error: Lightroom Classic CC running on an iMac w OS 10.13.2 and a total of 25390 photos in the catalog - 22648 have synced, and I have a folder containing 101 sync errors, but it won't tell me what the errors are, nor how to resolve them. If I click into the All Sync Errors folder and hover over the sync icon on any photo inside, it just says "Error syncing with Lightroom CC".
Would it really be the end of the world if LCCC showed what the errors were, or even had a realtime view of sync progress beyond a count of how many files are left to go?
And why are there nearly 3000 unsynced photos? I've marked all my collections for sync, which are the ones that think they know better than me where they should be?