splitting keyboard into 4 players bug

Hello everyone.
I am working on a local multiplayer game, and used the example from here to split the keyboard into 2 players:
https://docs.unity3d.com/Packages/c.../api/UnityEngine.InputSystem.PlayerInput.html

When im trying to split to 3, it works fine. BUT when I am trying to split to 4, the last player control scheme doesnt seem to respond.
my code:

var p1 = PlayerInput.Instantiate(PIM_component.playerPrefab,
controlScheme: "Keyboard1", pairWithDevice: Keyboard.current);
var p2 = PlayerInput.Instantiate(PIM_component.playerPrefab,
controlScheme: "Keyboard2", pairWithDevice: Keyboard.current);
var p3 = PlayerInput.Instantiate(PIM_component.playerPrefab,
controlScheme: "Keyboard3", pairWithDevice: Keyboard.current);
var p4 = PlayerInput.Instantiate(PIM_component.playerPrefab,
controlScheme: "Keyboard4", pairWithDevice: Keyboard.current);

can it be a bug?
all keyboards 1,2 and 3 are working perfectly.
Thank you,
Nir

 

nevermind, when creating the new control schemes for keyboard 4 i forget to add keyboard as required