Hello Ruben!
Not too long ago, I saw a hangout with John Mueller who got the same question and gives a logical answer. Here's the URL at timestamp 46:06 https://www.youtube.com/watch?v=i_xnKznRNCc&feature=player_embedded#t=2766
I'd transcript if I had the time, but it will take you a couple of minutes. It essentially says that even though it is embedded, it won't access that block of content because maps.googleapis.com/robots.txt blocks it. If I understood wrong, please let me know!
I had the same problem where part of my content was coming from the pins INSIDE the map, but since it was blocked, it couldn't reach the content itself. Had to do a workaround
Hope it helps!
EDIT: Just jumping back in to say that you should look back at your site. Seems like Google can correctly crawl its own map and the content served through it. Our site has no more problems related to this. November the 15th I still had issues, but today I've tested multiple times and it looked okay.
Croy