Currently in legacy Primo, a Subject is(exact) search returns items that do not have the specified terms in the visible records, but returns matches from the CDI metadata that is not presented in the record. For clarity of functionality, returning only results that include the specified terms would be preferable. (Similar to NERS 8871 which was focused on the Title fields.)

(An alternative would be to increase transparency of results so that the CDI metadata that constitutes a match is visible to end users.)