When a question on meta has been asked before, it is closed as a duplicate.
This is true even if the original:
does not have an answer at all; or,
does not have an answer that fully addresses the problem (anybody can "answer" a question about why a feature exists or doesn't exist or works the way it does, for example, but that doesn't mean the asker's problem has been "solved").
When the question is closed, it inherits this text in the body:
This question is an exact duplicate of:
However after the question (and any comments), with my emphasis on the points I don't like:
This question has been asked before and already has an answer. If those answers do not fully address your question, please ask a new question.
I think it is more likely on meta than anywhere else that the question has been asked before but does not have an answer (this happened today), and happens often when people think a question is so old that it is being ignored, and a "new" question might breathe some life into the issue.
What I don't like about the current wording is that (a) it is logically and factually incorrect in cases like this, and (b) it encourages the asker to ask the same question a third time - not only if no answers exist on the original, but also if they don't think the answers there address their concern(s).
The point of closing as a duplicate is because the question has been asked before - not that it has been answered before (or answered to the satisfaction of the new asker). My suggestion is to change the wording so that it's clear that a question shouldn't be asked again even if the original hasn't been answered (or answered to the asker's satisfaction). Since the asker only sees this text after 5 community members (or < 5 + a moderator) have deemed that the question is, in fact, a duplicate, perhaps as simple as:
This question has been asked before.
Or if we want to encourage the edit and reopen path:
This question has been asked before. If you feel there are aspects of the issue not covered by the original, please edit those details into your question.