Is AC working as intended?

[Randore]

Hello all, not sure if this is the right place to post this but was hoping someone could clear this up.

As a warrior on P1999 I have noticed as I have went through the levels that anything above a blue con has been doing significantly more damage to me regardless of AC.
At lvl 34 with an unbuffed 674 AC I can take minimal damage from blue cons in mistmoore, however as soon as I come up to a yellow con, I am taking near full damage from most hits as if I am not even wearing armor.

Is something wrong here or am I just being crazy?