Same issue with me (and same router) - I've tried the other solutions on reddit such as turning off a setting in location services for wifi - still nothing. Have yet to see anything connect on the router side when looking at the client tables per interface. I've also tried to have the same SSID as well as different SSIDs. When I separate them out, I get the same result you do. When I have them as the same, it always connects to the 5. Stumped, and, bizarrely, the internet doesn't seem to know. Crazy!
Same issue with me (and same router) - I've tried the other solutions on reddit such as turning off a setting in location services for wifi - still nothing. Have yet to see anything connect on the router side when looking at the client tables per interface. I've also tried to have the same SSID as well as different SSIDs. When I separate them out, I get the same result you do. When I have them as the same, it always connects to the 5. Stumped, and, bizarrely, the internet doesn't seem to know. Crazy!