Running ownCloud Server 10.0.0 (stable) on Linux (Debian jessie).
I uploaded a ZIP file (609MB) last week.
Switched to a different desktop machine, running Debian Stretch, and noticed that above mentioned ZIP is downloaded again and again.
Going back to original desktop machine, the behaviour wasn't seen.
Todady I started my Windows (desktop) machine, and noticed that all files were synced, as expected.
After the complete sync, the above mentioned ZIP is downloaded here again and again too.
The Synchronisationsprotokoll doesn't have any message regarding this file or behaviour, as the client deletes the relevant entry as soon as the next sync of this file starts.
For a short moment I saw the notice, that the "checksum doesn't match and the download is resumed". But not sure, if I remember correctly.
I already did at server site: occ files:scan --all
Please update to the newest 10.0 and client version. If the issue continues, please file a bug in the github repo as this needs deeper analysis. Maybe test with a smaller zip file.