There was a problem 1400E - Clear the Multiset in Educational Codeforces Round 94 (Rated for Div. 2) (yesterday's contest) and it got difficulty 2200.
Why is it strange? It wouldn't be, IF...
Get look at this 448C - Painting Fence. Yeah, these problems are same! In fact, even editorials for them are same.
As you've already guessed difficulties are different. Actually 448C - Painting Fence got only 1900!
It looks like that such a huge difference is a result of their positions in problemset (E and C exactly).
Of course, this situation is rare enough to be a huge problem. But more tasks more similar situations. Anyway for now it's just a strange fact.
Also I want to thank sevlll777 as a person who found 448C - Painting Fence.
What do you think about this?