Flag for "not an answer" declined seems broken. The user Michael Gaskill voted to close it, and is listed as a close voter, but it doesn't link to their profile like it should. I know that the user wasn't deleted because it still has the link to their profile in the Close Votes review task for the question.
There was a duplicate account for him that got merged.
The details in the close notice record contain the original merged user id (now deleted), though the close vote has been updated to the current user id.
As far as I know, we do not update the details in the close notice record.