maybe this was supposed to trigger for afterEvent Entity Hurt
but this trigger in afterEvent Entity Die when you throw a Splash Potion to an Alive entity(s)
which is supposedly trigger when the entity is Dead from Splashing Potion and not alive mob

I'll send an attachment below for you to see what is actually wrong

Step to reproduce:

1. Create a world and activate the addon, you must activate beta API from experimentals
1.1 (optional). test to see if the script is working by killing an entity normally
2. Summon or find an entity then throw an Splash Potion (any type)
3. See the result

(Sorry if my grammar is too bad, im too lazy to grammar check hehe...)