DMP seems not to be working on Soldier's Brooch

I casted Death Wish while wearing Soldier's Brooch (which says it has death magic protection). The spell backfired and toon died.

However, same toon when wearing Warrior Helm (says it has death magic protection). When spell backfired, about half his health was gone.

So it seems to me that maybe the DMP from Soldier's Brooch is not implemented?

Found answer on channel, for those trying to understand the mechanics of the game :)
DMP works to say protect your hp to say half but if your alignment is good, then the dmg is double and in that scenario a full death can happen.

Thanks NightKing for clarification.