[Poltava]

I think it is somehow map-related.

The problem is not general but pops up for some people, so I guess it must be some glitch in the installation of the map. I can mention that the same thing actually happened to me, with another campaign using the same map. Then I tried it on another machine, and then it worked.

One suggestion would be to remove the map completely, and reinstall it. But I'm not sure that this will fix it.

Strange, strange.