I believe the extra underscore interferes with the parsing of the taxonomy_id string. This is the first time I have had to deal with a taxonomy that had an underscore in it and it is the first time that get_field has not worked for me.
I’m trying to rule out issues. I’ve already checked spelling. Not sure what else to try.
Welcome to the Advanced Custom Fields community forum.
Browse through ideas, snippets of code, questions and answers between fellow ACF users