Quoting parrottmath, reply 38
I agree, but this might narrow down where the bug is occurring. I was just curious, since this problem needs to be address.
Vetrar and the other bosses need to be programmed to stay within their borders. There is no reason for them to be outside of their borders. These guys function ingame to provide a cool bonus and new settleable area when they are dead. That's it. They are not meant to be the rampaging one man offensive armies that they are now.
I'd like it if they're still the rampaging one man offensive armies they are now if they smashed the AI cities like human cities instead of taking care of AI cities and attacking only human cities and even more so with each city they destroy = expansion of wildlands.