Yea, as the mod stated, most of the maps need a lot of reload for it to work. So you have to keep trying. It eventually works though.  
 

What did you do specifically to make it work? I had been trying to load it with my friend, we both have the same game_mod version and are both using the Steam Bo1, unfortunately after several tries hadn't been able to make it work as the loading bar just loads in but turns grey and nothing happens... Does the host have to map_restart or does he/she need to restart the whole game altogether? Or is there a quick way to reload the map. Would appreciate if you could help