Files mirrored when not changed

[Mailbags]

I have a mirror FFS batch job set up to move changed files from a Mac HD (MacOS Ventura 13.2.1) to an external HD connected to a Raspberry Pi (file system type: fuseblk). This has been running fine without any changes by me for a couple of years.

Since January this year FFS has been identifying some files that are unchanged as needing to be mirrored, and then mirroring them across to the External HD. Before the Compare, the time stamps on these files are identical on both Left and Right so I am unsure why they would be selected for mirroring. After the mirror job runs, the time stamps remain unchanged. However a copy of the file is added to the 'Deleted' folder on the Right side each time the mirror job is run. (This is how I noticed the problem - the External HD usage is growing because I am using the time-stamped option for Deleted files; the Deleted folder is getting fuller and fuller despite files on Left matching files on Right).

This is not happening for all files, just some (maybe 5 GB of files out of the 400 GB I am monitoring). There doesn't seem to be any common features of those files, it looks like a somewhat random selection.

I can fix my disk space problem by changing how Deleted files are stored, however I would like to stop this continual copying of files over the network when it is unnecessary.

Any clues as to what might have happened recently, either to FFS, or maybe how MacOS might handle file metadata?

(Running FFS 12.2 but was also a problem on the previous version).

Many thanks.

[xCSxXenon]

Run a compare and see if what FFS says the differences are