We have literally hundreds of Composer templates. When the template includes a reference to an author in the author service, it appears that a number of metadata details from the author service are copied into the template (and then into any articles created from the template) as referent_properties which then show up in the credits.by objects returned by the Content API. These supercede the corresponding live entries in the author service even when the author's entry has subsequently changed.
This has the effect of turning Composer templates into little inadvertent time capsules of whatever was in an author's entry in the author service at the time the template was created, which will continue to be applied as referent_properties to new content going forward even if the entries have since been updated in the author service. This is a bit of a metadata management nightmare.
It seems that site service metadata is handled in Composer templates purely as references, and this better fits the data model of inflating from whatever's live in a relevant service. Perhaps the same should be true for author metadata?