Why doesn't Reaper Form's Bloodmoon Reaver convert Vile Shroud?

It seems like other skill conversions (e.g. Blood Font in Aura of Decay) include resistance types provided by the skill. However, Bloodmoon Reaver converts Reaper Form from a Necro tag to Physical, yet its Vile Shroud node still gives bonuses to Necro and Poison resist instead of the expected Physical and Poison.

Intended or bug?

its definitely intended, I imagine AoD is the exception to the rule since its a skill that revolves around inflicting yourself with the ailment/damage type it deals.