In the two latest firmware versions for the Asus RT-N66U router there is a bug in the popup display you get when selecting "View List" of network clients on the Network Map Screen. In both versions 378.56_2 and 378.57 the popup window takes a while to pop up and when it does it logs you out and you have to login again. This is quite repeatable. With version 378.55 the window behavior is normal.