When she accumulates all 5 stacks and expends them with say, Leaping Strike (usually against rocks, but I did pay attention sometimes against a single enemy), they may not all activate, but it seems like none of them are? What’s the actual deal here?
Works perfectly fine.
Each stack does the 50dmg as promised. So if you did in fact collect the stacks properly, then you’d release the 50 x 5 along with that Leap Strike.
If you were testing it against a rock, then obviously it won’t work as the fury stack scans for units and not structures.