[This user](https://mirror.codeforces.com/profile/UnstoppableChampion) competed in Round #623 in Division 2 and received rating change for it, even though he was 1900+ before participating and this round wasn't Div. 2 only. How was this allowed?↵
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Update: I also noticed that there were several competitors ([here](https://mirror.codeforces.com/profile/kiyoshi0205), [here](https://mirror.codeforces.com/profile/pandrei), [here](https://mirror.codeforces.com/profile/DeadlyCritic), and [here](https://mirror.codeforces.com/profile/ZieiN)) who competed in the Div 1 version but were rated for Div 2. Again, I'm not sure how this was allowed.
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Update: I also noticed that there were several competitors ([here](https://mirror.codeforces.com/profile/kiyoshi0205), [here](https://mirror.codeforces.com/profile/pandrei), [here](https://mirror.codeforces.com/profile/DeadlyCritic), and [here](https://mirror.codeforces.com/profile/ZieiN)) who competed in the Div 1 version but were rated for Div 2. Again, I'm not sure how this was allowed.