In this diff, InternetArchiveBot changed 3 refs from 'live' to 'dead'. The edit summary is "(Rescuing 3 sources and tagging 0 as dead.) InternetArchiveBot (v2.0.1)" which seems incorrect, I assume it should say rescuing 0 sources and tagging 3 as dead.
https://en.wikipedia.org/w/index.php?title=Calgary&diff=967188503&oldid=967130522
Thanks
As I understand it, the bot actually "believes" that it is responsible for adding the archives as well, because it is switching a formerly live link to "dead" and adds the archive information, which happens to have already been added previously. It would only report "tagged as dead" if it did not find an archive.
What Cirdan says is partially correct, also to that end it's only flipping a switch on the Cite template but the cite template will render the output completely differently, putting the archive URL first now, rather than second in the reference. That is considered a rescue.