Colisseum - Working as intended?

I understand the frustration but when an attack doesn’t land it is an evaded attack. As far as the system is concerned it’s either a hit or an evade, whether it happens naturally or is forced by a buff or debuff.

I would either try to time the use of blind to when you land Undermined from Kleya which should prevent turn meter gain, or try to time it to where the second AOE is on cooldown enough that if the walker does go again it doesn’t immediately hit you with 2 AOE’s back to back. Otherwise, just forego the use of Blind, as much as that sucks.  Against that boss it’s too much of a liability.