Refiner's Bargain, Equipment with rarity conversion seems to be 10x as high

The first line of Refiner's Bargain which states that Equipment with rarity dropped from possessed monsters is converted to Thaumaturic Dust with 5% probability seems to trigger a lot more often. It seems to trigger for >50% of the monsters and 100% of their drops.

Maybe I'm really just (un)lucky but I took it mainly for the sulphite conversion.

Btw. I speced in Torment and Rogues, so it happens quite frequently.