Does an updated chapter in a book count as a new publication?
As a non-answer, but perhaps worthwhile, we could note that literal publication, revised publication, and so on, literally serves scholarly purposes. The potential objection is that this might score status or impact points unfairly. The error here is thinking in terms of status or impact points, especially as a back-forming regulator of permissible behavior.

That is, the real goal is not status/jobs/tenure – although those are serious things – but advancement of human understanding. In particular, rules of the game of status/jobs/tenure are not at all necessarily connected to issues about advancement of human understanding.

In particular, there’s nothing to treat. If some for-profit publisher’s self-promoting “impact factor” somehow counts this twice, this is no serious human being’s problem. The possibility that a corporation’s software misunderstands a new edition is in no conceivable way an ethical failure of people who write parts of something useful enough to be republished in a new edition.