Stalker Dark Melee Assassin's Eclipse issues

[garthander]

I started playing my first stalker but realized there has to be some issues with Assassin's Eclipse. The power says it can be interrupted if you move or attack while hidden. I can be standing still, not being attacked, activate the power and then after it takes the endurance it just stops and I have to click again, rarely it will happen 2 or 3 times before it works properly but its a 50/50 every time I click the power that its going to work properly. I can understand just not activating, but its annoying when it doesn't activate but takes the endurance anyway.