Hi Leon,
While reassigning to a new routing, which operation of the new routing did you select to place the SFC at?
The status of SFC is defined by WIP.SFC.STATUS_BO field. For Done, it is StatusBO:SITE,405. For In Queue, it should be StatusBO:SITE,402. This is just for the case if you decide to update them directly in the database. But the system might need to run some additional validations or changes, for example to qty's of Shop Order. If all of the validations are done correctly by Change Production but the problem is only about SFC Status, then a direct change of the status might work.
BTW in fact, fixing a production data via forum posts is a quite fearless move. Maybe you'd rather consider opening a ticket.
Regards,
Sergiy