sync finishing failed, being used by another process.

Hello, as you can see above, sync process has been completed almost. But target file can not replaced because it’s been used by another process. I check and found target file been used by Open Source Continuous File Synchronization, that is to say, it’s being used by Syncthing self but it can not be replaced by new version, is it a bug of Syncthing? Please confirm it. Thanks.