Is it a bug or unaccepted answers also show up in this section?

• hmm... cat jokes? – AccidentalFourierTransform Mar 5 '17 at 14:18
• This being a network-wide issue, the answer is to be found on the network wide meta: meta.stackexchange.com/questions/18870/… – dmckee --- ex-moderator kitten Mar 5 '17 at 14:27
• You might want to charge your battery. 9% is pretty low. – Kyle Kanos Mar 5 '17 at 18:04
• It is remarkable, though, that one question managed to get seven different answers without a single one of them getting an upvote. – Emilio Pisanty Mar 5 '17 at 20:53

The Unanswered Questions tab shows questions that have no answers with a positive score nor an accepted answer. (That includes questions with no answers at all.)
This is intentional, and it reflects the fact that just because someone has added content through the answer field it doesn't mean that the question has actually been answered. The Unanswered Questions tab is meant to get you to questions that have not been sufficiently addressed, and the criterion as posed does as good a job as any number-crunching machine algorithm to do that.