What do you people think ? I'm looking this thing from PvP perspective.
The damage should still land, which is what it does. Outright applying flat DR rather than splitting up the attack (since a tank can actually shield/resist/dodge/etc an attack that comes at them through Guard) would be pretty much borked. Since a Guarded healer could simply heal themself with a tank next to them and just outright never die. With the damage roughly split 50% between the two of them, the damage is high enough that you'll eventually die from atrophy.