Not trying to gravedig, but I had the same issue.
I have a similar setup with AMD CPU and Nvidia GPU bound to a Docker Plex.
I believe what happened to me was that I had the GPU connected to a monitor to observe POST, and when UNRAID at some point when the SAMBA portion came up, the Plex Docker was spun up as well and grabbed control of the GPU, suppressing any further output to my monitor. I believe the behavior would be the same if a VM had control of the GPU instead of the docker.
So when it looked like UNRAID had froze, it actually completed startup and was successfully up and running, only not output anything to the monitor because UNRAID didn't have the GPU anymore.
If you have a similar configuration, before you assume that UNRAID had failed, double check your web interface and see if it's up and running.
