From: Santa Rosa, CA
Thanks for the saves. I ran your save and I see what you mean. Once surrounded, they are in a "hex isolated" but they are still listed as they should as being "in supply" (I have a way to confirm that). In both cases when I attack them surrounded and when I attack them not surrounded, their CV crashes and they lose the battle badly. I don't see any extra combat disadvantage going on due to isolation. However, when they are forced to rout by the fact that they have nowhere to retreat, and they start taking additional losses for that, there may be some factor kicking in that puts them over the edge (the units are not in great shape) that causes them to surrender. In other tests I've just run of units just surrounded (many not in great shape), they are routing out as expected. So will you be able to count on units surrendering just because you surrounded them in the current turn? I think the answer is no. Is it possible. Yes. Is it possible that the heavy snow on the ground is impacting this, I can't say for sure. I don't think so, but without a thorough audit through the code, it's impossible to say.
All understanding comes after the fact.
-- Soren Kierkegaard