The same thing happens with two machines connected via an Ethernet cable, which appears to be what this USB4 network feature does - an Ethernet NIC to software, but with different lower layer protocols.
AIUI, most NICs these days do what is called "auto-crossover"; i.e., they'll detect the situation and just do the "crossover" in the NIC itself. A normal cable works.
The same thing happens with two machines connected via an Ethernet cable, which appears to be what this USB4 network feature does - an Ethernet NIC to software, but with different lower layer protocols.