If a library does not set the system preference, NoIssueCharge- by leaving this blank. Koha will not checkout items to any patrons who owe any amount of money. The alert box (yellow) will display and give no words on what the error is. Can we add wording to the system preference that a dollar amount should be in this system preference and also, have the Yellow alert box indicate some notation about the error.
I don't see this behaviour on master - can you confirm it's only on 19.11? For a change I think it would be nice if we allowed deactivating by leaving empty, as that would make it more consistent with the other fine limit related prefs.