The automatic defeat happens because of the difference in maps. The user path takes maps made with the in-game map generator. This map generator does not put any start positions in the map, it just does a layout. When the game reads this map, it then assigns start positions.
Galaxy Forge maps need to have defined start positions, so if you put a Galaxy Forge map in the user path (where the in-game generated maps are supposed to go) the game gets horribly confused because it expects a map with no starts, and thus you get your auto-loss
