Here are my observations from further testing. The NC client installed on my MacOS (latest version with security updates and Norton Internet security) incorrectly reported “green check marks” in the Finder synce folder. Thinking it was finished, there was still transfer activity in the background that wasn’t obvious. Even down in the sub directories I was transferring, there was a green check mark telling me it was synced. I suspect the zero byte files are “place holders” for the upload process similar when you have a *.part when downloading in Firefox.
Before I discovered the above, I copy/pasted some test folders that were previously zero bytes. They immediately became available and could be opened – much faster than a re-upload could provide. This seemed to kick off the rest of my transfers.
This issue (for me) seems to only happen when I try to transfer a larger number of files. 10GB of photos. So I echo what others have stated on this.
I setup a second NC server (Ubuntu 18.04 / latest stable NC) within my home LAN. I tested transferring the same data set. While I had different syncing issues, My data correctly synced in the background. (transferring pics from the iPhone photo gallery using the NC auto sync feature).
I suspect that the NC client is having issues with my basic Godaddy shared web hosting. I have the Linux Deluxe account with shell access with them.
Also noticed that in my bulk file transfer, the job returns an error in the client when it hits files ~25mb + – “server replied 503: service unavailable”. My internet connection is rock solid and suspect that Godaddy shared hosting doesn’t like me syncing a large amount of files in this way as GD package I got wasn’t meant to be a dropbox like replacement. While the sync job reports as finished again by the NC client, it seems to still be going as I am getting MacBook popup notifications.