Clients want re-download all files issue

I have an issue with my ownCloud 9.1.6 setup (OS is Raspbian Jessie Lite).
The issue has started when I wanted to delete some useless chunks files into the "cache" directory. I've tried the occ files:cleanup command but 0 orphan file was found. So I've deleted manually chunk files and I've launched an occ files:scan myuser. Since I've launched this command, all my Windows clients want to download all files again.
Is it normal ?
And now some files can't be downloaded, I have a "Connection closed" or "Operation canceled" error.
How can I do ?
Thank you !