It seems that the new Novatel 4510L 4G LTE hotspot will periodically go dormant in the middle of an active web surfing session. I am still connected via wifi to the hotspot, and can log in to the admin page to see that it has lots of bars and battery power, but is dormant. After several minutes (or, nearly immediately, if I power cycle it) it will become active again so that I can surf the web.
Is there a firmware update coming soon to fix this? It's pretty annoying.
For more information on the 4510L dormant/dormancy issues see this thread: