RT-N66U (380.57 or 378.56.2) freezes when I click on client status in Network Map

With the last two releases, 380.57 and 378.56.2, when I click on the round button above "View List" in the Network Map, it takes a while to open the status window and then it freezes. Nothing is clickable and when I reload the page it logs me out. This is in Firefox. I tried Chrome and IE and they both crash with similar symptoms.

Now I'm back to 380.55 and have no such issue. The client status open without a delay and everything runs smoothly.

View attachment 5337 ...

RT-N66U (380.57 or 378.56.2) freezes when I click on client status in Network Map