If a Weighbridge ticket which does not require Proof of Delivery (POD) returns to weigh in but the Weighbridge ticket status does not update, you will not be able to invoice the Sales Order.
To resolve this issue:
Navigate to and open the Weighbridge ticket.
On the Reference tab, use the Delivery Verification function to add another return weight. This will update the rest of the process and give the return weight that it should have had when it was weighed in.
Try again to invoice the Sales Order.