My modem and router (TP-Link Archer C5v) are in the control room in my house.  The M5 main is connected as Router (Default) to a wall port in my living room.  I set up a main network and a guess network in the TP-link Deco apps.  Why is the guess network able to access router information of TP-Link Archer C5v as well as private network ? 

Then I reconnect the M5 main as AP to the same wall port.  The guest network is still able to access router information as well as private network although I have checked the "Isolation" button.

Did I set up correctly ?  Kindly assist.  TQ.