@george1421 Update.
So we did some more testing and it turns out that the Intel Volume Management Device setting in our system BIOS is whats causing the issue with our NVMe drive. We found this because even after getting FOG to successfully push an image to the drive, Windows was unable to boot from it. We disabled the VMD setting and the PCI device is no longer addressed on an extended root hub and Windows booted normally, so we tested this with the orignal bzImage as well and it all still works as expected.