With a Wi-fi analyzer, you will be able to find that the Archer A7 v5 / Archer C7 v5 has 2 SSIDs on each band.
One of them is the normal SSID, which can be detected and connected by the wireless devices.
The other is a hidden SSID, which is used to build up the OneMesh wireless network system. It cannot be detected by the typical client devices like laptops or smart phones.
See the picture below:
Here is another similar situation submitted by a user.
Like the existing Deco mesh package products, the hidden networks are equipped automatically with a highly secure random password which aims to keep the security integrity of the wireless network.
This hidden network is by design, and it not a symptom of the device not operating properly.
For more information about OneMesh, please read this article: https://community.tp-link.com/us/home/stories/detail/722