[otrs] "Pending reminder" where should be "closed"

I'm writing a little stats script to do some custom stuff and I've just noticed that the state of some closed tickets is still "pending reminder" I thought once a ticket has been closed the reminders stop, and that would also update the state to "closed" but this doesn't seem to be the case.. Is there some cron process that should have updated the state field in the ticket table ? rgds Frank