I have seen someone mention this problem before, but I can not find it again.
Anyway, I am able to show [map query="all"] however after countless permutations I can not get [map query="tag=my_tag" format to load any markers.
[map query="tag=cycling" overlay="true" disable_scroll="true" show_images="false" show_posts="false" height="200px" width="100%"]
Shows zero markers. I am going to recreate all the posts and see if that is an issue, but in the meantime, perhaps there is a simple fix I am overlooking.