Question about receiving input with blueprint

I have a really annoying problem with input receiving.
I have 8 pawn actors in my level. I made my code done, and used event dispatchers to dispatch the mouse events to the level blueprint. In the level blueprint, I have exactly the same code for each pawn (except the references and the events get from the dispatcher).
It seems alright and the pawns are all the same. They should work the same even it is not working. So I tried to play it, for the first time, all the pawns are working well. And I tried again (without changing code), I got my problem. 4 of my pawns are working and the others are not working*.
The pawns that can’t work is seemed to be random selected. And the way I set is like this:

         P5 P4
P8 P7 P6         P2 P3 P1

And the ones works are P1 P3 P4 P5

I really need help.

Additional Information:
They are all created the same blueprint and the blueprint is inherited to c++ class (empty c++ class inherited to the default engine pawn actor)
All the actors I’m using are using paper sprite. And I used an empty PaperGroupedSprite to be the root of the other sprites (the PaperGroupedSprite is an early access class).
The auto receive input player is the local player.

*The ones don’t work means they can’t receive any mouse inputs from player. These are tested on both level blueprint and Pawn blueprint.