Update This happens by simply hitting the enter key several times quickly while in the search bar of Discover.
@skearns64 reported this on hipchat, and I reproduced it a couple of times on k4.4.
It happens if you click the search magnifying glass quickly repeatedly on the discover tab.
We both had Shield installed. Don't know if it matters. I haven't tried without Shield yet.
Steve hit it with Firefox. I hit it with IE 11 and Chrome
When you "Go back" with the button on the error page, you do tend to lose your time range selection and/or filters you applied but didn't save.

Update This happens by simply hitting the enter key several times quickly while in the search bar of Discover.
@skearns64 reported this on hipchat, and I reproduced it a couple of times on k4.4.
It happens if you click the search magnifying glass quickly repeatedly on the discover tab.
We both had Shield installed. Don't know if it matters. I haven't tried without Shield yet.
Steve hit it with Firefox. I hit it with IE 11 and Chrome
When you "Go back" with the button on the error page, you do tend to lose your time range selection and/or filters you applied but didn't save.