If you check out my campaign on Steam - http://steamcommunity.com/sharedfiles/filedetails/?id=576007033. Right at the beginning, a truck arrives and the cutscene ends. You'll notice though the truck never arrives. It's because it has exploded on the road to the right of the player's position (you can see the pillar of smoke). This is also happening on later missions too.

EDIT: I've implemented a fix by disabling damage on the vehicles affected; also, it seems to have something to do with the process of exporting missions from the 2D editor to the 3D editor, as only missions exported in this way are causing problems.

Problem occurs since update. Affecting most subscribers. If you need to look at the scripts, from the intro scene, just check out the init.sqf.