Background of the issue:
I am trying to add a translation to a custom post type 'post', and to have that translation adopt the taxonomies from the original language post.
Symptoms:
When I translated a new post and clicked 'Publish', the taxonomies were not synced.
Questions:
Why are the taxonomies not syncing for new translations after publishing?
Is there a different step required to ensure taxonomies sync automatically for future translations?
I got an email asking if I still needed help. Since the core issue is not resolved, I prefer to leave this ticket open until we no longer need the code provided for the interim.