Trying to upvote one's own answer resulting in incorrect highlighting

[InSyncWithFoo]

Steps to reproduce

• Log in to SO
• Go to a question to which you posted an answer
• Try up/downvoting your own answer

What happened

SO highlights the vote button, but quickly retracts it and says: "You can't vote for your own post".
SOPU highlights the answer's corresponding box; that box remains highlighted until the page is reloaded.

What should have happened

The box should not have been highlighted. Self-voting is not possible.