I made a poor decision on this post, and agreed with the existing close vote. That automatically upvoted the close-comment with an orange upvote.
I re-read the question though, and realized that I actually disagree with that duplicate close, so I retracted my vote. I tried retracting the auto-upvote on the answer though, and was unable to. If I click the orange up arrow to undo it, nothing happens. It stays upvoted.
This likely isn't a problem on my end. As a test, I upvoted a plain comment and gave it a blue upvote. I was able to successfully remove my upvote on that comment by clicking the up arrow again.
I'm guessing this is a bug?
Why do I think that this is a problem? The upvote doesn't do anything directly, but I don't want it to show artificial support for the close. While the number of up votes on the comment shouldn't effect the chances that someone else will close vote, I'm willing to bet it does have some influence.