Signet of stone
Yeah the toughness is a passive effect, so when you use the signet, you lose the passive effect.
also shouldnt this be in the classes category?
That’s how signets work. A signet has a passive effect and an active effect. The Passive effect is just a small bonus whenever the signet isn’t on CD. When you use the signet, you put it on CD and thus you lose its passive effect, but you you or the enemy gain the active effect, which could be a teleport, AoE conditions, reset on certain CDs, immunity to power damage. As soon as the CD of the signet is finished, you regain the passive effect. So when Signet of Stone isn’t on CD, you gain toughness, but as soon as you use it, you are immune to power damage for a duration and then you must wait for the CD to finish before regaining the toughness.
It’s a known bug, and a conspiracy. You’re being cheated out of the benefit. Anyone who tells you differently is a troll.