Three Windows 11 PCs connect via Wi-Fi to a tp-link AX3000 router. When connected, the Network and Sharing Center on the PC shows two active networks. Both active networks are attached to the same wireless SSID. The first is my "Home-Network" SSID. The second is "Unidentified Network".

What is this network? Is it a security risk? 

When I set up my iPhone as a wireless hotspot, my 3 PCs connect with only my "Home-Network" visible on the PC. The "Unidentifed Network" does not appear.

Points

1. This issue happens on 3 Windows 11 PCs. So it isn't just a configuration issue on one PC.

2. This issue happens only with my tp-link router, not an iPhone hotspot. This suggests the tp-link router is the source of this "Unidentifed Network".

Mark