I've tried all of this exactly as you offer.
Connected 1 and 2 LAN cables, applied full last firmware update BMC, BIOS, FRU/SDR. Right after update the sensor's value was 0x0000. But after 30-60 minutes of uptime it switched to 0x0010. If I disconnect LAN cables it switches back to 0x0000 with the same delay ~30-60 minutes.