GeForce GTX 850M driver issue on ubuntu 20.04

I have an issue after update my drivers on ubuntu 20.04
After reboot I see black screen
A lot of details in attached file (219.2 KB)

nvidia-bug-report.log.gz (266.5 KB)

Let me know if anyone from NVIDIA replies to you. I have an vaguely similar issue with my GTX 780Ti card, but have had no responses.