Node duplication when creating new content

I have noticed some strange effect, and I suppose it comes from the interaction with pathauto. When I create a new node and it gets autosaved, a node is stored in the database, but pathauto assigns it a name. After that I save the node I was creating and I finally have two nodes (or probably more than two), some empty, some partially edited. I don't know what more info can I give so this problem can be traced or duplicated. Perhaps pathauto doesn't understand about revisions? Because a new node, as per documentation, are autosaved as revisions.