Can you get a upload a log file %LOCALAPPDATA%\Turbulenz\Boundless\boundless_log.txt from after you’ve exited the game from a session when you have experienced the problem? On exit it writes some profiling information that may show up what is spiking high, it may not be a network if there is a stall in the game.
Did anything else change on your system? E.g. did you update of graphics drivers as Nvidia rolled out a new drivers early this week. If so perhaps try with SLI disabled as a test.
There is this website user put together that shows connections to the server to see if there is an obvious connection issue for you.