@rnaaijkens I take it you added the pcie carrier card yourself with two Kingston drives? Looking at the pictures you posted of your HL4, there isn’t a card installed I the x16 slot.
Also, since you have the HL4, you will have two available m.2 slots on the motherboard for drives. The HL8 uses one of those for the backplane but that wouldn’t apply to you. I’m thinking it’s possible that you’re seeing two drives on the motherboard and not any on the NVME card that you may have installed.