"On Input Touch Begin" does not fire blueprint communication correctly?

I am using the touch event “On Input Touch Begin” to trigger an animation and change the value of a variable from another blueprint (by calling an internal function). There is also an input action (key “P”) that starts the same sequence.

The touch event “On Input Touch Begin” does not change the value of the variable. The input action does it correctly.
It seems that for the touch event the variable is private…

Is this an expected behaviour from the Unreal Engine? Or am I doing something wrong? How can I fix this?