This question on Academia.SE has 15 up-votes and no up-voted answers. If one selects "Unanswered" from the top banner, it is not listed as an unanswered question.
This is the case for all questions with up-votes but down-voted answers, and seems like a very bad idea: getting a down-voted answer should not cause a question to be considered answered.
This is also contrary to the documented behavior described in prior questions:
In comments, it is claimed that this behavior is intended. If this is the case, then the bug is the description of the top-level "Unanswered" page, which currently says:
questions with no upvoted or accepted answers
but should instead say something like
questions with no upvoted or accepted answer and no downvoted answers