Increase deffence nod (bug or game mechanic)

Hello, my tests based on Energy Shield on Shield passive nod in witch area.

Energy Shield on Shield passive nod (says 40% increased Energy Shield from equipped Shield)
So I figure out that it gives es after local es on shield is applyed, for exaple 500es shield will give +200es. But after than this additional es from shield is not multiplied with any other %increase maximum energy shield (items, passive, intelect).

So, charcter with flat 2000es (500 from shield) and 200% increase max es will have 6500es + 200es (from 40% increase deffence from shield nod).

And character with flat 2000es (500es from shield) and 100% increase max es wil have 4500es +200es (from 40% increase deffence from shield nod).

so %increase max es/armor/evasion is not interact with (increase deffence nods).

Is is game mech or bug?

It's not a bug, it's just another increased modifier additive with other increased modifiers with the exception that it only applies to shields. However modifiers that give u MORE energy shield (Infused Shield) or other kind of defences will multiply the amount u gain from both increased energy shield nodes (or other defences) and increased defences from equipped shield.

Example stats:

130% increased energy shield
40% increased defences from equipped shield
15% more energy shield

700 energy shield body armour and 500 es shield will give u a total of (700*(1+1,3)+500*(1+0,4+1,3))*(1+0,15)= (1610+1350)*(1+0,15) = 3404

ok I see, but why it is addative before %increase max es work on shield?
I mean logicly I get extra 200es from shield it is energy shield, it is flat es added to my flat es so should work with %increase max es? In other way nodes with increase es or deffence on shield is looks to weak simple 10% increase maax es (in average with discipline flat es around 2500) benifit more than 40% from solid 500es shield right? and to get this increase defence from shield is hard to get from three.