I have a raspberry pi running linux with an NTFS external HardDisk mounted with ntfs-3g. The normal read-write of this HD is very good. However, while I edit a file on other devices that synchronize with this HD on raspberry pi, no matter the device is Windows or Linux, a lot of sync-conflits are generated. I was pretty sure that only one device was used to edit the file.
I tried everything such as file owner, attributes, etc. with no luck. Eventually I formatted the HD on raspberry pi to linux ext4 format instead of ntfs. It finally settles. Everything is fine now.It seems that there might be compatible issue in ntfs-3g on linux that caused the problem.
Syncthing expects sensible behaviours from the underlying filesystems, and I guess that is not happening in this case, with file modification timestamps moving around, or something along the lines etc.
I guess best option to understand why the conflicts are happening is look at how the files are different.
For example, i edit a WORD file by typing in new text on a device and save it to local disk. Pi will generate a sync-conflict file which is a version before the local save is made, without those newly typed text.