According to the manual :
M.2_1 shares bandwidth with PCIe x4 slot, when M.2_1 is populated with x2 device, PCIe x4 slot will run at x1 mode, when M.2_1 is populated with a x4 device, PCIe x4 slot wil be disabled.
I seems like the NVME is recognized as a x2 device or i might be wrong.
I have...