[Priest] Prayer of Mending is not proccing from certain sources of damage

Prayer of Mending is supposed to proc, heal and bounce when the target takes damage (this should not include environmental damage or Life Tap).

Currently there are many sources of damage that do not do this e.g.

Magtheridon's Blast Wave channeling

Netherspite's Nether burn aura

Eredar Deathbringer aura passive

It only appears to only be working properly from direct damage. This is a major nerf to what is arguably the priest's best healing spell. Same issue with Mana-Shield for Shamans