Player Controller Get Input Touch State can not update each tick

Hi there
I want to detect 2 touch input, to change scale of an actor. So first, I should get the location of both touch point, like this


However, when I keep touch down and move finger, the location can not change

the location can only change when my finger remove from screen and then touch on screen
So how can I get the touch location of all touch point each tick?
Thanks a lot!