BoA trinket not reduced in Timewalking

The WoD BoA trinket for agility users

Infallible Tracking Charm - Item - World of Warcraft

isn't being reduced in damage inside Timewalking.

For it to work you must:

1. Equip the trinket outside.
2. Proc the trinket outside.
3. Enter the timewalking dungeon and enjoy the crazy damage!