Recent update of Google Maps is successful at associating the maps to the post using the [location] shortcode.
However, from what I can tell, the show_posts="true" is not setting the flag in the created map so the link to the post is not clickable in the map popup.
Is show_posts supposed to add that type of functionality, and if so it may need a look to see if there is something amiss. I have manually selected the show posts checkbox in the options admin and the link is not directing to associated post that way either.
I'll take a look around but if you have any insights, I am all ears.