Pixnub face detection uses the GPU. So face detection won’t work if you turn it off with either the new or the old plugin versions.
The GPU compatibility is the issue for sure. You may want to contact Adobe on this. It could be that your graphics card is no longer supported by Photoshop. I don’t really know. Adobe can answer those questions better than I could.
I can help again tomorrow on this. However, I will be gone all day today and not back until late tonight. I have to leave now to drive my boy to a college campus tour so I won’t be able to help out at all today with this. So I suggest contacting Adobe to see if they can fix the GPU issue for you.
Let me know what they say.