Button lag on android

Hi, I have an issue I simply cant resolve.

I have a tab button setup that loads a panel when clicked using an array. This works 100% in the unity editor and have a debug that lists the array number when clicked.

But when I build and send to my sony z3 it sometimes requires the button to be pressed multiple times before it works. It highlights the button, so its picking up the press, just not executing the task.

Is this a delay on the phone side because I don't experience the same issue with the pc and its driving me crazy!?

Using onlick event in button, linking it to the specific array

I have set the repeat delay in the eventsystem to 0.1 and it still makes no difference

 public GameObject[] furnitureButton;
 
     public void SwitchItem (int aID) 
     {
         for(int i = 0; i < furnitureButton.Length; i++) 
         {
             if(i == aID)
                 furnitureButton[i].gameObject.SetActive(true);
             else
                 furnitureButton[i].gameObject.SetActive(false);
         }
         //Debug.Log (aID);
     }
 }

Thanks