Defeated droids don't deal bonus damage

Hello all

Is this WAI?
We tried to use Zaul, Sidious and 3 random droids in offense to see how the bonus damage works against 5 Hans.
When the first droid died, all of them took damage and got inflicted burn.

With the second and third none of them was damaged or hurt.

Why???
It says "whenever a droid is defeated he deals..."????

https://youtu.be/JLiuN2lgnPk