its happens to me also, and get the game unplayable. It only stops when i die and start spectating my teammates. Some images to clarify:
while ingame-http://i.imgur.com/SrEMnNC.png
same game after dying-http://i.imgur.com/V3g6pr0.png
I use the ping test program and it shows packet loss near 100%.
If and wargaming developer needs more info from me just ask. I want this game to be perfect and if i can help ill be happy to.