Thorns doesn't apply on some enemy's attacks

I've realised that some attacks don't get reflected to the enemy nor heal me via leech. I have the helmet that applies thorns to all attacks.

I had this feeling while leveling, but in the last area of act 3 (act 6), before fighting Doriani, I found some specific example that was destroying me.
The enemy was called "archer transcendent". It throws arrows. Thorns ignored 100% of these attacks. I hope that helps.

I´m in maps, and I´m 100% sure this monster doesn´t proc thorns. I get destroyed on maps where it is present. Please fix it as soon as possible.