Hello I'm having a similar issue with a Samsung SSD in a 4x4 PCI-e bifurcation card. I've used this in 2 other OS's on the same hardware with no issue so it is something to do with QEMU or Unraid. I cannot figure out how to view the logs unfortunately. I've gotten the card to work a few times, but it wont work after rebooting the VM. I can usually boot the VM by trying again after the error, but there is no disk visible. I swapped the NVME card to another slot on the bifurcation card, after which the SSD was visible in the VM, but again after rebooting it dissapeared. I've tried reinstalling Unraid, several different VM configs, and chanting in Latin while booting up but no luck :/