NBP filename undionly.kpxe
Well NBP refers to a UEFI system and you are sending a bios (legacy) mode boot loader to the target computer. Bios and UEFI are not compatible. You should be sending ipxe.efi for a uefi based computer.
When I change the DHCP bootfile name to boot\x64\wdsmgfw.efi
Umm, this is a WDS problem/issue not FOG.
If you are using FOG and have a Windows 2012 or newer DHCP server this document may help you create a dynamic boot file that will support both bios and uefi clients pxe booting.