If I downvote a question or answer, and the post is edited, it looks like I can make one another downvote. However, when I click the downvote button again, the result appears to be exactly the inverse: instead of downvote I upvote.
I believe that this is the same situation for upvotes (producing down the second time instead of up).
Is this a bug?
Actually, both tooltips (up and down) informs about undoing the action - even if you didn't any up/down vote - "...(click again to undo)". This is a little embarrassing.
Let's say I voted on a topic. Then after some time I visit the same topic and I don't know anymore if I voted it or not (sometimes the voted topic is highlighted (up or down), sometimes not - it's not a rule). So I decide to vote this topic down, but in fact I undo(?) it, or even reverse(?) it. I never know.
After the first up/down usage the up/down buttons tooltips should change.
For example, in the downvote situation: the downvote button should have a "undo" tooltip text, and the upvote button - a "reverse" tooltip text.