I am getting the same problem. Using Cisco Meraki, Windows NPS and Smoothwall for radius accounting.
Users can authenticate fine and gets an IP address however I get no internet. They have to turn off Wi-Fi and turn it back on and you can browse straight away. Really annoying.
I have confirmed from Meraki they are sending the relevant attributes, but Smoothwall diagnostics still showing otherwise.
Anyone tried sending accounting to Smoothwall from NPS instead? Or have even come across this issue?