@Stan` solved it for me, I was having the same issue with that same thread yesterday. EDIT: I'm having that issue again right now!

https://wildfiregames.com/forum/topic/169808-map-making-support-and-conversion-tool-post-atlas/ For whatever reason I seem unable to access this thread: 

Thanks for all the work on this, @victorcrimea. I'll try to test this on Windows soon.

Cool stuff! Did you make the models or did you take them from somewhere?

The shininess is defined by the spec map, and it should be dark where the hay roof is uv-mapped. Maybe you are using different materials in the .xml actor files and in some cases spec map is not taken into account and in some cases it is?