So we played it again this weekend and indeed with the mission installed on both Xboxes the weather problem was fixed.
Well, the mission is a very good one, full of tension and action but we tried to beat it on Vet mode with no success. I dunno, but regarding reality this seems a bit out of balance. There's a town full with Russian elite troops and armor to protect it. The town is complete in the open, no cover worth mentioning except a few bushes and lone trees. We tried a dozen ways from all directions, with splitting troops and trying to blow up the supply trucks from somewhere out of town etc. but we always got eliminated. The problem is not so much that there are so many enemies around outnumbering the players squad, but the Russian tanks - the T 80 to be specific. The west side has only 9 men and even if you can manage to get into the town and killing the soldiers, the T80 is able to "swallow" that many hits with a LAW or even a stronger AT weapon that this always meant total elimination for us within some minutes.
One has to be silent to get as near the town as possible, the M2s (great to place them in the windows!) could be killed by sniper shots, but as soon as our squad was seen in the open we got pinned by the Russians and then the T80 came around the corner. That made it necessary to switch weapons for the At team to defend us, but that cut off the firepower against the infantry, further limiting what one lone squad can do in this situation. There's no way to attack the enemy from farther away (because of the fog) and to lure them into making an attack themselves, comming out of town, which would improve the players position as defenders before they make a counterattack against the town.
So, when I think about it I would suppose that this job of clearing the town is certainly not a job for one squad. It would be better imho to have two basic squads so we could make a more powerful pincer move to distract the enemies, or to have at least one armored vehicle on the west side. The armor would help to cross the open ground with armored assault tactics and could defend the infantry against the T80 while they make it into the town. The armor wouldn't play a big role in clearing the town because that would make it vulnerable to street fighting so in town it would still be mostly inf vs. inf.. I think it would help to make the mission more realistic as a military operation.
Cheers,
Andreas