It turns out you were right, it triggers becuase the splash potion kills itself when it touches the ground which is in contact, however ive debug the damage source, and after killing the mob with the splash potion, it indeed says the mob died by magic, it's all good now 👍
It turns out you were right, it triggers becuase the splash potion kills itself when it touches the ground which is in contact, however ive debug the damage source, and after killing the mob with the splash potion, it indeed says the mob died by magic, it's all good now 👍