While in a VS3 drive on the paved road between Pustoshka and the constuction site NW of it. There are two of these invisible obstacles approximately halfway between the town and site, a few hundred yards apart. They seem to be more on one side of the road than the other. Traveling south on this road they are more to the left side, traveling north they are on the right. If you are driving slowly the VS3 will stop when it hits them. If you are going fast enough, you'll be pushed down through the terrain.

This is probably a separate bug, but if you are the passenger in a VS3 and someone else is driving and you fall through the terrain there appears to be a possible exploit where if neither of you get out of the truck, and the driver logs out (making the truck disappear) the passenger reappears on the surface of the terrain, but seems to be invisible to other players.

While in this state other players cannot see you, you cannot interact with things, but you can still shoot weapons. Haven't tested this against players, (not that I wouldn't have if anyone else was around to test on) but I believe this could be exploited to become a silent assassin from which no one is safe.

Logging out of the server and back in seems to correct the issue, but when you log back in the server creates a corpse on the spot where you fell through the ground, with duplicated items. Another possible exploit.