Boldur's Lore Legendary

Completed Boldur’s Lore challenges today, and was sorely disappointed to find it has a passive that literally does nothing.

It reads: “Boldur Only: When Ekkuni Greatshield breaks, gain 0% to all damage for 4 seconds.”

Am I reading this wrong? Is it supposed to be 4 seconds of invulnerability? Or is it supposed to give a damage bonus?

It’s bugged. It’s supposed to give you 25% damage, and has been acknowledged as a bug.

Thanks much.