I had a question from more than a year ago (Aug 2011) here, which was upvoted 5 times and favourite twice. There exists a high quality (+12) and accepted answer on this question.
In the last couple of days, it has received another random upvote, then quickly afterwards it was closed as dupe by five low-reputation members. I do not mention "low-reputation" disparagingly, but instead to indicate that a few of them only just barely above the 3000 rep required to cast close votes, and each of them is below the 10k required to see it in the closure queue using the 10k tools. How did the 5 users all find this old question suddenly?
That attractive-looking duplicate is actually inaccurate (and I was able to get the question reopened), but that's not what this meta post is about. I'm more interested in how does this sudden closure happen? Did the upvote place it in some sort of recent activity area where it has received increased visibility, and then one close vote somehow snowballed into the necessary 5 votes?