That is not a right on the facility, that is a standard manufacturing agreement.
NWBO has a contract with Advent to manufacture some (unknown) amount of DC-L. It says nothing about the facility.
Any customer of a contract manufacturer will have a contract to get product manufactured. That is the business. Advent will have other customers with contracts that require Advent to manufacture. That is how the business works.
At present the contract terms look like they suck for NWBO. We know as fact Advent can walk from the contract as a huge winner. The reason they do not is NWBO pays them far more than any rational customer would.