If a court rules an adjudicator's decision to be a nullity, is it legally permissible for the losing party to refuse to pay the adjudicator's fees?

This is still open to legal interpretation. Based on past legal precedent, courts have been eager to demonstrate numerous different ways that an adjudicator can claim fees, and that the referring party is responsible for these fees in the event of a nullity. However, it seems that the potential for a referring party to put an argument before a court that it is not liable to pay fees under these circumstances remains open.