I have the IRIX lenses however I don't have the PL mount so I can't really guide you here. I would do an exchange with B&H and see if the second lens also gives you an issue. Additionally I would reach out to IRIX customer support and ask them as well. I have found that they usually take a few days to respond however so you might have a replacement lens by then.
I had a friend test a Sigma lens using the Sigma MC-11 and they had the asme issue pop-up. Still photography is good but video AF either doesn't work, or hunts forever. Rendering it useless. Apparently this was an existing issue before the A7sIII was released as well. Seems like the only solution is to use e-mount lenses.