I was reviewing this question in the Close votes queue and upvoted the comment that mentioned the correct duplicate. I received a message regarding hitting the vote limit. I proceeded to VTC the as the flagged duplicate and the system happily accepted that.but I was somewhat baffled by the message. I am unaware of a limit on comment voting. Is this a rare bug that I've stumbled across or is there indeed a limit on comment voting? If the latter, what purpose does it serve?