Thanks for a quick reply.
I don’t think I made myself clear however.
I am trying to submit A POST request via REST api. According to the docs for rest api https://docs.metabox.io/extensions/mb-rest-api/ to submit field values, one must pass in a field called meta_box.
This works fine for creating a post. However, when using your terms extension, and passing in the meta_box parameter, the same does not work.