This SO post goes over the semantics of `--inplace` and `--no-whole-file`

  --inplace                update destination files in-place
  --whole-file, -W         copy files whole (w/o delta-xfer algorithm)

It is very important to debug rsync scripts with a test corpus and not on live data, preferably on test vm or container.

https://superuser.com/questions/576035/does-rsync-inplace-wr...

Also, when transferring from different systems, make sure that both rsyncs are of a high enough version, again preferably the same.

MacOS ships with a really old version of rsync that doesn't support extended attributes at `/usr/bin/rsync`

   rsync  version 2.6.9  protocol version 29

This is kinda a large footgun.