PatronDuplicateMatchingAddFields behaves differently for null values depending on whether the null values are in the existing patron record or the record being created. To replicate: -Set PatronDuplicateMatchingAddFields to surname, firstname, email Scenario 1: -Create patron A with a first name and surname, but null email -Create patron B with a first name and surname matching patron A, but a value in email -----> NOT FLAGGED as duplicate Scenario 2: -Create patron A with a first name, surname, and email -Create patron B with a first name and surname matching patron A, but null email -----> FLAGGED as duplicate It seems that the two scenarios should behave the same way, or that there should be documentation of the different behavior in the manual. This applies to 40082 but is also true for duplicate matching in the staff interface.