However, when I attempted to vote to close, I was asked to select the duplicate, which I did, and was greeted with a message I had not seen before:
This question does not have an upvoted or accepted answer
and the "Close" button remained greyed out:
In the time that it has taken to write this question, someone else has successfully voted to close as the count now stands at (2).
Has there been a change to the way this works?
Do you require a certain amount of reputation to close as a duplicate if there is no accepted or upvoted answer on the propsed duplicate?
Is this a just a bug?
Update: now that a second vote has been cast, I am able to select the duplicate and vote to close.