I don't have as much experience with 10G compared to older Ethernet standards, but I'm wondering if this is some sort of auto-negotiation problem. I believe there are some 10G interfaces and SFP+ modules that are 10G-only, and others that are multi-speed (sometimes called Multi-gig or mGig). The Marvell AQC-113 that ASUS uses is a Multi-gig interface; supporting 10M, 100M, 1G, 2.5G, 5G, and 10G with auto-negotiation. I wonder if there's some sort of incompatibility between your SFP+ module and the Marvell Multi-gig implementation.
The Marvell AQS-107 SFP+ module should be fully compatible with the AQC-113 on your motherboard, as they both use the Marvell Alaska mGig PHY. You would need to check if it's compatible with your router, as there can be compatibility issues between routers and particular SFP/SFP+ modules.
Something else to note is that the AQS-107 product info says that it has a maximum cable length of only 30m at 10G. That is less than the 55m on Cat 6 or 100m on Cat 6A in the 10GBASE-T standard. If you have a particularly long cable, that could possibly be a problem. You don't need Cat 8 for 10GBASE-T, Cat 6A is sufficient (or even Cat 6 for up to 55m), although I don't see any reason why it wouldn't work over Cat 8.
Lastly, the newest Marvell AQC driver is 3.1.7.0, which is probably worth trying if you've not already done so.
Edit: You could also confirm basic function for your interface by connecting it to a simple gigabit switch and seeing if the link comes up ok. That would obviously limit the speed to the speed of the switch, but is a simple test to see if the interface and driver are working at a basic level.
