Recently stumbled upon a question that has been put into close votes queue twice:
As far as I can tell, question entered the queue second time after first round votes on it expired and someone else cast a new vote.
Is it good or bad that question may hit the close votes review queue more than once?
Please note this question is not a complaint about review item shown to someone more than once, because this is not what happened, I just discovered above reviews by occasion.
My search at MSO so far led only to brief and very generic explanation of the queue purpose in tag wiki:
view and act on posts by other users that the system thinks may need attention.
Close votes (and probably reopen) queue being "reentrant" in the way described above apparently is intended to speed-up the process of making a close / leave open decision.
For the first round reviews, I believe it is commonly agreed to be a good thing, but I have not seen an explanation for why such a decision speed up is considered good for next round(s) of voting.
My current take is that this is rather a good thing.
Due to the fact that queue doesn't show to reviewer questions they already voted on, it helps to faster bring attention of more reviewers, which in theory leads to more thoroughly considered decisions.
But there may be also considerations against this that I just somehow missed.
For the sake of completeness, "reentrant queue" also probably speeds up "close / reopen wars". But I am neither convinced that this would be an ultimately bad thing, nor have seen this widespread enough to warrant concerns.