I have a pair of AC1750 B1 routers connected with Ethernet in an AiMesh network with wireless backhaul disabled. A couple of days ago the one that is the node was not providing WiFi. The WiFi light was flickering normally but it wasn't transmitting. The primary was fine. I rebooted the node several times and even tried a spare 1750 B1 but there was still no WiFi. Then I rebooted the primary node and when it was back online I had WiFi from the node. It hasn't happened again. Any ideas on what happened?