rsync error 23 can be triggered by many different reasons, which are not clearly specified
due to that, unbalanced plays it "safe":
- it flags the command producing the error 23
- does not remove the source folder/files which triggered it
this gives you a chance, as the content owner to
- check if the files in the destination look ok (probably a spot check or more thorough check if you have important data)
- allow you to remove the files on the source, via th rmsrc button on the history page, if you find the folder/files state to your satisfaction
to recap, rsync error 23 is too vague to be handled automatically, so it requires some user attention in order to validate the transfer