Heads up, Rune Priests and Zealots – a recent patch made you more vulnerable. Actually, it removed an exploit, but still…
Used to be, if you used Grimnier’s Shield/Embrace the Warp AND a tank put you on guard, you took zero damage. Unlike a lot of other things that are multiplicative, the two 50% reductions in damage were additive. (ummm, in othe words: most things would do 50%, then 50% of that, so you’d still take 25%.) The situation still isn’t “normal”. Instead, you cannot use the self-buff if you’re guarded, and cannot get guarded if you’re using the self-buff.
Not known right now is if it’s an over-write or a failed action.