I came across an (old) question in the reopen review queue that was closed as a duplicate of a deleted question (I'm assuming the duplicate was deleted later, though I don't have enough rep to check). However in this particular case the first question should probably have been closed as "Not constructive".
In general what is the correct action to take in such a case? Should the question be reopened so that it can be closed properly? Should it be left closed and flagged for a moderator?
In this case I voted to reopen, my reasoning being that I thought it was a poor user experience to have a link prominently displayed at the top to a deleted question.