Slitherine

Why are Soviet units considered out of supply when they cross the Persian border?
In previous versions this didn't happen.

Germans counterattack and, as soon as they cross the border, THEY are considered out of supply!

There is reduced supply in North Africa and the Middle East. Persia is considered to be part of the middle east.

We had to add some code to prevent supply from crossing between the European mainland and the Middle East. Otherwise Allied Middle East would get full suply via Russia and Persia.

The effect is that supply doesn't cross between Persia and Russia. So in order to be in supply on the other side of the border you need to capture a supply source on the other side.

What you have is a very unlikely situation where the Russians face the Axis in Persia. In most games the Allies control Persia and there won't be a battle zone there.

Your issue is probably possible to code around as an exception, but you might risk full supply flowing out of Russia and into the Middle East causing supply issues elsewhere on the map. So it's a big dangerous to work on the supply code to fix an issue that will occur very rarely.