The first post (or reply) after a Poll cannot be edited. I'm not talking about the post with the Poll itself but the first one after that.
That post has both the "edit" and "full edit" buttons.
Clicking Edit gives the error message in the red banner at the top of the screen and the edit button disappears.
Clicking Full Edit gives a 404.
This happen both with a post made on your own poll and one from another user. It also happens with both type of polls.
Win 7 64 bits, Chrome Version 25.0.1364.97 m