It doesn't seem stronger, it is stronger. Before 2.0 update the blue circles were the same as your level, not 10 levels higher but after the update, they increased the difficulty. People who did the instances before the update will tell you it's super easy because it was, but now with the 10 level gap it's like impossible. Yeah before the update the pains were level 80, now 90. Thank goodness i beat that level before update...

When did you do the instances? Before or after 2.0 update?

Hmm I wonder if there's any changes to the chapter 9 instances.