What causes Nova's Triple Tap to go on a short cooldown?

Question

This isn't about the level 20 ultimate talent.

There is a brief "arming phase" where Nova locks onto her target before shooting three bullets. When something happens to her target during that phase (allied Devouring Maw, Divine Shield, etc.), sometimes Triple Tap is placed on the full 100 second cooldown, other times it is placed on a much shorter 10 second cooldown.

What triggers this 10 second cooldown?

1. Is this a timing issue? I believe if she is interrupted after the shots start going out, Triple Tap is always put on the full cooldown. Maybe I'm just seeing the ability get blocked right as the first shot goes out?

2. Is this ability-specific? Does stunning Nova have a different effect than a Devouring Maw or Void Prison on her target? And is that different from a Divine Shield/Sanctification on the target?

3. Is this determined by whether the line to the target was interrupted by an ally or an enemy hero? For example, is there a difference between an allied Void Prison and an enemy Void Prison on the target?

Answer 1

The idea behind the ability is she takes aim and then fires the 3 shots. If she gets stunned/knock backed during the taking aim part of the channel you get the 10 sec cool down.

After the first projectile is traveling you get the full duration of the cool down.

As I already mentioned above, the channel only gets interrupted by knock backs/stuns, the roots dont affect the channel in any way and you just keep going.

Devouring Maw counts as a stun and stops the channel. Void Prison on the other hand is a special case. Everything in the bubble is essentialy frozen in time, so your channel stops, but continues after the bubble breaks again.

To find out the exact timing for the "taking aim part", someone would have to measure the times before the bullets fly and test it in a private game.