Losing the Game Abruptly? Need Help

[MarechalJoffre]

My friend has been having this trouble as Germany in two separate playthroughs, namely losing the game while everything seemingly is going alright. The game ended abruptly on September 14 on both occasions. Here's the "Soviet Union has won this game" screen he has been getting.

Here's the central and northern portion of the front along with relations and here is the southern part with score highlighted.

Save file is here.

So far we have been unable to find out why this keeps happening. Any help would be much appreciated!