Parent blueprint triggers overlap events while child blueprints don't.

I am using a simple shooter ai from the market. I also bought some skeleton meshes to make my own ai.
The shooter ai asset pack had a parent blueprint with all functions implemented and a child bluperint which was inheriting the parent. Perhaps the asset maker intended to duplicate and modify only the child blueprint. However the child’s collision isn’t working. I set all collision settings on both parent and child’s skeletal mesh component but still only the parent’s collision worked properly.

bullet1
bullet2

This is my bullet’s collision. It is set on bullet’s static mesh.
*Currently, ‘No Collision’ is changed to ‘Collision Enabled(Query and Physics)’

parent1
This is both parent and child AI’s skeleton mesh collision settings.
Keep in mind that ‘generate overlap event’ is enabled and a tag named ‘BODY’ is added only in AIs’ skeleton meshes in order to distinguish overlap events easily.

character
parent and child’s root component is fixed with a capsule component.

2023-05-29
This is what I have. The player blueprint is not a child, nor a parent. It is just an independent blueprint. As you can see, I can get hit but the enemy wouldn’t.
I assume that the problem is about how collision works in child blueprints.

Why is this happening?