Two days ago I got some very obvious serial downvotes on SO. (Four downvotes on four old questions of mine, in a short space of time shortly after someone replied to a comment of mine on an an answer of theirs I downvoted.)
After a couple of days, the detection script noticed and fixed three of them but left the fourth, so I flagged the question it was on explaining what happened.
Today, I find that flag marked as not helpful and the downvote still in place.
Why would this be? Can the admins not see the revoked downvotes, only the remaining ones? Or if the script missed it as well, is it likely to be a coincidental vote from someone else?
(Obviously it's a tiny amount of rep involved; I'm curious as to the process.)