A Change of Rater and Non-Rated Time have nothing to do with each other. Someone was responsible for that NCO and owes him a COR. If your 1SG is stating that he was unsupervised, well, then that's his story.
Either: A) Have the NCO write an evaluation covering him from last September and submit it back through his unit, or B) you simply pick him up from that time. The longer you wait, the more likely that option "B" is going to happen whether you like it or not.
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