Issues with spirit barrage Xbox one

I’m use the barber in the cube and it states stop casting and it will explode doing damage with spirit barrage.
I’m using manitou on spirit barrage but on a YouTube video it says cast for about 5 seconds then stop casting as boom everything dies. I’ve tried this and nothing happens the only way I get the skill to work is by dying myself. Am I doing something wrong or is the a way to trigger the effect. I have tried stopping and casting another skill but that doesn’t work.
Please someone shed some light on what I’m doing wrong.

Your pet casts spirit barage the entire time it is alive therefore it never stops until you die. Use a different rune.

Any suggestions on a good rune?

I noticed it on the switch
Phlebotomize if you need health, like for pushing solo this is a good heals.

I think it might actually be a bug, it isn’t just the xbox version it persists on the Switch too.

Here is an explanation

if you just cast it they will explode once you have done the amount of damage that is needed to kill them.

the game counts how long you will need to cast it and then they will explode. thats how i do, maybe im horrible wrong but doing gr100 with ease