Gallery post format bug

Hi,
First of all, how to use Gallery post format correctly? I have found no docu in this respect. Right now I have inserted gallery code in exerpt field and the gallery appears at the top of the post as a slider. But there’s a bug: the slider shows ALL images uploaded to media gallery from this post. Even if the image is NOT displayed anywhere on the page – it still goes to the slider. How can this be solved??

If I insert a gallery somewhere at the top of the post, the bug persists, PLUS, the gallery appears as a slider AND as a normal WP gallery below..

The page I need help with: [log in to see the link]