ERROR: The Inventory Part in stock object does not exist.

I’m in APP9 and have 2 work orders that are project connected. We have used move serial to inventory functionality to move the serial object into stock. I’ve confirmed they are in stock and project connected. The work order status was reviewed, all postings are authorized and all lines are not invoiceable on the transfer to customer order screen. When the user tries to change work order status to Finished, this error is received. I’m unsure how to resolve this issue and didn’t see anything in other posts with this same issue that would help me.