I'm not sure you understand. It's not that they're being overrun. It is, as I understand it, that they're being killed LITERALLY the second they spawn. The Russians at the 2nd line all spawn in a single (or maybe two) rooms towards the rear of the bunker complex. There's a long hallway leading out of the back of the bunker complex onto a hill, and then back towards the village. This is likely in place to allow the Russians to escape through the tunnels when the 2nd line is finally taken.
Thing is, without the spawn protection (which has now been added, so hopefully this will be a moot point across the entire map), the Germans can approach this two ways:
1.) BEFORE capturing the farm, they send a small detachment of men to the BACK exit of the bunker complex at the 2nd line. The Russians will likely fall back and defend at the trench, since that's where most of the attacks by the enemy will come from. Any soldier killed at the trench line will soon spawn back at the one or two rooms where the Germans are already prone, locked, and loaded. They hose down the spawning troops, who never have a chance to shoot back even.
2.) The Germans capture the farm, and begin their assault. As part of the assault, they send a few SMGers around the back and into the spawn. Kill any Russian there, and then hunker down in the spawns to kill the russians as they spawn.
Consider the potential impact of this tactic. Two German troopers could, conceivably, lock up almost the ENTIRE Russian team. Get more Germans in there, and that's it. Game over for the Russians. All because people are willing to take advantage of the game convention of "spawning in" to a map.
This is, as I see it, dirty pool. It denies the enemy even the opportunity to fight back, and is basically shooting fish in a barrel. If that's what people want to do, I encourage them to either go kill the bots, or sit down with a shrink to work out their anger issues rather than purposely denying other players the fun of playing the game.
Unfortunately, there will always be people who will take advantage of loopholes like this, purely for their own enjoyment, so it's up to the mapmakers to ensure that it can't happen. Slyk has changed the map accordingly, so moving forward this won't be a problem.
Slyk, thanks for making the change. If you only made it for this spawn, you might want to check the other spawns out too for both sides. As a general rule, I believe well design maps need more than one exit from any spawn area, and approaches to those spawn areas need to be EXTREMELY difficult for an enemy -- like, lots of open ground, no place to really hide, etc. For enclosed spawns like the bunker, you're probably better off putting a temporary minefield around the area to avoid this.