I experience this problem, my theory is that it relates to what countries all 4 players are from, im from the UK, so 2 Vs. 2 with 4 people from the UK, i never get problems.
However i have some people on my friends list from other areas of Europe, now if i try to play with them, and say, two American players, i find it either lags terribly, or freezes up.
Thats how it is for me, might not apply to you guys.
It has nothing to do with what country you live in. The problem is that someone's connection isnt equal to everyone else's connection. Meaning that someone is lagging a little bit