If a movie/clip/scene is uploaded as part of a collection that same movie/clip/scene cannot be uploaded separately, bu the reverse is not true..
Has that rule changed in the last 12 months? What you say seems the logical thing to me, and I see that kind of upload all the time, but about a year ago jackny explicitly confirmed to me that the opposite was true - clips that are posted on their own after they were previously posted as part of a collection are not considered duplicates.