When an item that has been claims returned previously is deleted, the item no longer shows on the patron's account. I would prefer Koha to leave the name of the item or a place holder to be able to track claims returns better. Or perhaps a counter that is not dependent on the item being in the system.
Yes, we would absolutely like to track claimed returns on items removed from the system. We usually remove them pretty quickly, but still want them to be counted on the patron's record, to prevent misuse. It could still be an option, as maybe some libraries would prefer not to count them once the item is removed.