RT-N66U - Devices can't connect after they sleep - Requires airplane mode toggle

[FutureDancer]

Hi,

I just purchased a new Asus RT-N66U. I have a very odd problem. After devices wake from sleep such as my Windows 8 laptop (Intel n223 wifi) or Samsung S4 they have about 1 minute of wifi... then all internet stops working. It appears as though they are still connected to the wifi.

I have to turn each device on airplane mode and then off again to get it working

Any thoughts on what could be causing this?

Thanks,
Josh