Hi Richard, that's not related to nvidia drivers, I had plenty of those issues with IPR in past with older drivers too. Sometime it helps to unplug Kernel and re-connect it but sometime nothinge works until reload few times. IPR just says "done" too fast and renders only empty background or HDRI. F9 and F10 works fine but IPR sometime just gets that empty.
I've not managed to find sure replication steps but i did send some of those screen grabs to Juan last year but we didn't find cause of it sadly.