Supernova question

So I got a question. I got the Supernova assassination and it’s pretty sick. I’ve pulled it off once since I got it, but since then, I’ve only been getting default assassinations. My question is, do you need a plasma grenade to pull it off, or is the game hating on me?

The assassination requires a wide open area and level flooring to take effect. Otherwise you’d be tossing the victim through a wall.

I actually stopped using it since finding out about this. Plus, I like 104 Ways to Die for its TTK and low minimum spacial requirement.

Any assassination that takes more space to do than where you were when you did it reverts to the default slit throat assassination.

I use And Stay Down and it always fails when performed on a ramp.