X299X Arorus Master x8 slot bifurificaion issues

[screwtech02]

Just installed a supermicro NVME adapter card with 2 nvme drives, pretty obvious with 3 add in cards that Bifurification of the x 8 slots does not work within bios when set to 2x4. Curious if this is tested prior to bios release?

[screwtech02]

I have tried 2 different add in cards for using dual NVME drives in the x8 slots, and setting slots to x4/x4 pci-e in bios. Within windows only single drive is shown? Also, only setting for VROC is x4? And its a x8 slot? Anyone have any insight?