Guatelitzi's Thesis body armor bug

I’m not 100% certain yet – I plan to do more extensive testing later today – but it appears that Guatelitzi’s Thesis may not be functioning on body armour as its description suggests.

Based on my observations, one of the following may be happening:

Guatelitzi’s Thesis disables armour-based mitigation entirely
or
Some portion of incoming damage is being converted to Chaos damage

You can refer to my character WhyBearManAreGay for context.

Observed Behaviour
After equipping Guatelitzi’s Thesis, my character’s tankiness dropped dramatically.
Relevant stats:
~70% of Physical Damage taken as Elemental (mostly Fire)
In Bear Form:
~12k Armour vs Physical
~30k Armour vs Fire
Elemental damage mitigation:
76% Fire resistance
75% Cold and Lightning resistance
10% less + boosted adaptations

When hit by a normal white mob in a T16 map with a basic attack:
I take ~100–200 damage per hit
I receive almost no life recoup

Why This Seems Incorrect
I have (theoretically) 15% of prevented Physical Damage recouped as Life:
From the passive tree
From Guatelitzi’s Thesis

Theoretical scenarios:

Scenario 1 (expected behaviour):
A mob hits me for 1000 physical damage.
After mitigation:
~300 physical damage vs 12k armour
~600 fire damage vs 30k armour and 76% resistance
~50 cold/lightning damage
Final hit taken: ~100 damage (or even less if more than 90% can be mitigated via armour + resistance)
Prevented damage should result in ~135(900*0.15) life recouped over 8 seconds.
In this scenario, dying should be extremely unlikely.

Scenario 2 (observed behaviour):
A mob hits me for ~100 damage, but there is little to no mitigation applied.
As a result, almost no damage is “prevented,” and therefore almost no life is recouped.
From what I’ve observed in gameplay, Scenario 2 seems far more consistent with what is happening.

Also I get poisoned a lot, hence my suapision about conversation to chaos damage.


Summary
Equipping Guatelitzi’s Thesis on body armour appears to either:
Break armour-based mitigation, or
Convert incoming damage in a way that bypasses mitigation and prevented-damage recoup

I’ll update this post once I’ve completed more controlled testing, but at the moment this feels very likely to be a bug rather than intended behaviour.