Transcendence still applies armour to physical damage

With the Transcendence keystone, armour is meant to apply only to elemental damage, but I'm 99% sure it's applying to both physical and elemental damage.

I haven't been able to play this league but a friend is playing a Boneshatter build I made and we realised he was taking far less physical damage from Trauma stacks than he should have been. After testing on Kuduku, we calculated he was mitigating the trauma damage as though he had 90% pdr when he actually only had about 66% from things like end charges/watchers eye etc.

Hope this is enough information for ya GGG.