Having been playing multiplayer recently, I've noticed a consistent behaviour of VON channels (especially global and side channel). Other players have noticed it too as the effect is quite clear.

The fix goes as follows: If you want to talk understandably (without lags) in those channels, you have to first keep the transmission open for about 20 seconds on those channels, which apparently clears some kind of cache. After completing this, the VON lag gets noticeably smaller and makes your transmission understandable.