Error when changing Quote SalesRep

We recently had a Sales Rep leave and are now adjusting his name off of old quotes to the new person. While doing this we have run into an issue where we are getting an error (attached below) during the change. We can not do anything with the quote past this error but we can close it and re-open it and then make the change for the SalesRep.

Anyone have an idea why?

Is the Old Rep marked as Inactive in workforce maintenance? If so change them back to Active and update.

They are but shouldn’t that error pop up every time in that case? Or is it a 1 time per quote type error?