Slitherine

I had thought that partisans were supposed to be limited to the boundaries of their home country, but in my most recent game I've seen several partisans move outside of their countries' borders.

Is this historically accurate? Would Yugoslav partisans have really made a dash for Sophia, for example? Or French Resistance headed toward the West Wall? I assume that partisans existed in no small part because of the support of the local populace. But when the Resistance crosses into Germany, I guess that support would vanish, no?

That is not a bug. You as the player move the partisans. I would say that if a partisan can move far from the home country then the Axis player isn't doing enough to prevent it. If you rail a unit close to the partisan and get adjacent to it then you pin the partisan since it's out of supply.

I don't see a problem with French partisans moving towards the Siegfried line to destroy empty fortresses there. You easily prevent that by having a unit stationed in Strasbourg.

Partisans aren't a problem if you garrison several of the cities in the occupied countries. Axis minor units are good at that. Even Italians do better against partisans than fighting in the front line in Russia.