- free the current level before taking down other things on exit.

Nor doing so can cause memory corruption when the object hierarchy gets deleted later which may still reference some stale data.

source/core/gamecontrol.cpp

@@ -582,6 +582,7 @@ int GameMain()
 		r = -1;
 	}
 	//DeleteScreenJob();
+	if (gi) gi->FreeLevelData();
 	DeinitMenus();
 	if (StatusBar) StatusBar->Destroy();
 	StatusBar = nullptr;