Updated the title, as I discovered that the same regex is used to try and extract and match subject headings in bib records to authority records in the biblio.extract_metabib_field_entry function (and thus could similarly create false matches between a bib record and an authority record).
Updated the title, as I discovered that the same regex is used to try and extract and match subject headings in bib records to authority records in the biblio. extract_ metabib_ field_entry function (and thus could similarly create false matches between a bib record and an authority record).