We have the system preferences CalculateFinesOnReturn and CalculateFinesOnBackdate to make Koha calculate overdue fines as an item is returned, either in place of or in addition to the fines cron. However, if one marks an item as lost and has MarkLostItemAsReturned enabled, the issue will be ended without an overdue fine being calculated. We should add the option to calculate an overdue fine at the moment of marking an item lost.