I am the coordinator of Round #810. I will be brief and clear.
The div1E problem was copied by one of the two authors, it was not a coincidence.
For this reason, the div1 part of the round is unrated. Div2 stays rated.
Sometimes known problems appear in a contest, it happened to me as an author and to any problem setter who has organized many contests. This is never a reason to make a round unrated. Today something different happened, the problem was deliberately copied and the author did not tell anything to anybody (not even to the other author). Codeforces (and me personally) condemns this behavior.
A final personal remark: I feel sad. Please future authors: do not copy problems. It's a waste of everyone's time.