I believe it has something to do with the proxies being messed up.
A few days ago, I joined a game and got proxied to 3 people, and had weird pings with them, approaching 300, even though we were all from North America. My pings with the other people who werent proxied were normal, around 100. The game lagged even though all sim speed were 4 or higher, and no spikers from what I saw. Kind of weird since all my pings were still under 350 despite the weirdness of it all, maybe there was another pair of players for whom this wasn't the case.