I occasionally see "exact duplicate" questions appear on the review page despite having configured my filters to exclude it. This seems to happen when a question has close votes for multiple reasons, i.e. "exact duplicate" or "too localized".
I think the filtering is a great idea otherwise!
Okay, so this is by design; guessing the query just asserts something like this (oversimplified) condition:
WHERE reason IN (list of checked reasons)
Is there a chance this could be turned into something like this?
WHERE reason IN (list of checked reasons) AND reason NOT IN (list of unchecked reasons)