Apparently it was set to hidden before it was triaged, but left hidden after it was closed and the status was changed. There is nothing in the UI that indicate

Apparently it was set to hidden before it was triaged, but left hidden after it was closed and the status was changed. There is nothing in the UI that indicates it is hidden. They said it was a known issue and they won't fix it, so it doesn't make much sense to keep it hidden.