Peculiar USB 3.2 Gen 1 Splitter Issues in Windows 11

Hello!

My Motherboard, a B550M DS3H from Gigabyte, claims that the USB3.2 G1 header onboard supports two ports. I have no idea how. But my front panel has 2 ports, and I only have 1 header. My GPU covers up all available PCIE slots.

I purchased one of those cheap USB 3.0 splitter cables on Amazon and hooked up the two front panel ports (one is USB-C, through another adapter).

Whenever I plug in a USB thumb drive in either front panel port, it shows up twice in Windows file manager. One of the copies works, the other shows as unformatted by windows.

This seems wrong. Do you have any ideas how I can fix this? I do not know how to access the two USB 3.2 ports mentioned in the Motherboard documentation that the header supports.