What are you referring to by 'Base Stat"? For example In my tank build I have 3 max Evade and 3 max Defense all elaborate and passives contribute 753 def and evade. So on paper the base stat of each is identical. In this scenario I will receive the Defense proc (7% glance) HOWEVER upon adding the Evade agent and increasing my Evade by 500 points above my Defense I will instead now get the Evade proc (5% Evade) This scenario also applies to the Waist guard Belt.
The way I understand it works is it looks at which stat is truly more beneficial within the ratio of def/evade that you have given that Def is 70% mitigation on glance and Evade is 100% mitigation.
With my example specifically you have the following calculation:
-
NO AGENT (Stats Equal)
44.9% Glance : 31.4% Evade
0.7:1 (ratio of damage reduction)
31.43:31.4
Therefore Glance is determined to be of higher value and Talisman buffs Glance % -
WITH AGENT (500 more Evade rating)
44.9% Glance : 34.4% Evade
0.7:1 (ration of damage reduction)
31.43:34.5
Therefore Evade is determined to be of higher value and Talisman buffs Evade %