Until 23.11 a null value/blank for system preference noissuescharge effectively disabled it. Beginning in 23.11, null value functions like 0, blocking patrons with any amount in fines and fees from checkout. Libraries that do not want to have patrons blocked for outstanding fines are putting in an arbitrary high number as a workaround. I can't find anything in bugzilla or release notes indicating this as an intentional change in behavior. See bug 25219