(Sorry for another complaint about a missing badge. I really seem to be dogged by bad luck in this respect.)
According to the "Badges" page, the requirement for earning an "Enlightened" badge (which can be awarded multiple times) is
First answer was accepted with at least 10 up votes
I have earned the "Enlightened" badge eight times so far. About 19 hours ago, my answer to "Guidelines for customizing biblatex styles" -- the first and (so far) only answer -- had gained its 10th upvote and had become accepted. None of my other "Enlightened" answers had been downvoted to a score of below 10 or had their acceptance revoked, so according to the rules I should have earned a ninth "Enlightened" badge. This hasn't happened so far, though.
I'm aware of a potentially crucial facet: "Guidelines to customizing biblatex styles" is one of my own questions, so it was me who accepted my answer (after it had gained a score of +10). However, I rummaged through Meta.SO and didn't spot any rule or statement saying answers to own questions aren't eligible for the "Enlightened" badge.
I'd really like someone to shed light on this matter.