While looking at some unrelated issues in the d.org queue for Token 8.x, I noticed a new setting in the UI, which we don't have:

This seems to have been added only in the 8.x version, with https://www.drupal.org/project/pathauto/issues/2773573
GitHub Issue #:
4755
Recent comments
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Thanks Alejandro. That was the clues I needed.
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