Nextcloud dekstop client sync problems. Expected filesize error

We have one laptop and one intel NUC. Both are running windows 7 and haas the latest nextcloud desktop client installed.

On the laptop everything works as it should for the user. But on the NUC it hangs randomly and never finishes syncing all the files.

Logfile on the server say
message":{“Exception”:“Sabre\DAV\Exception\BadRequest”,“Message”:“expected filesize 1830992 got 196608”,“Code”:0

This has been seen on nextcloud 15 and 16 with desktop clients 2.5.1 and 2.5.2

And from what i found when searching for it several other has had similar problems. But no real solution or real bug found either.

Server is running nginx and php fpm 7.2 on debian 9 (that are up to date)

This is really strange. We found one pptx file that differed 1kb in size. When we removed that one for the user and replaced it with a new version everything synced. And no more problems.

The really off and strange about all this is that all the files in the error log that had problems where in different folders and different types of files all over the place that had nothing to do with this pptx file for that user.