Just a guess as I’m not sure what your setup is. You’d have to show us a screenshot of the blueprint with the Print String not firing.
The thing is that it’s not the Print String that is the culprit here. I’d blame scripting logic.
I mentioned keys consuming input as this is the default setting:
If you do this in 2 different actors and in the Player Controller, only one of the actors will fire, consuming the input. The controller will not even see it.
Actors also need to receive input first in order to register it.