Problem snapping object on phone, but fine on PC.

I am developing for an android phone (Samsung S7) using google VR SDK for the cardboard.

I am trying to create a script that allows a cube to be dragged and dropped and then snapped to another cube when the objects are close enough. The script works perfectly when on the computer.

When I build and run on my phone, the cube can be dragged and dropped. However, the cube does not snap to the position of the second cube when close.

I have attached the whole script but I think it is the last if statement that is screwing up:

  using UnityEngine;
  using System.Collections;
  
  public class DDCube : MonoBehaviour
  {
      private Vector3 screenPoint;
      private Vector3 offset;
      Ray ray;
      float distance = Mathf.Infinity; //Infinite Distance
  
      public void Update()
      {
          int layer_mask = LayerMask.GetMask("Cube");
  
          ray = Camera.main.ViewportPointToRay(new Vector3(0.5f, 0.5f, 0.0f)); //Centre of the screen (i.e. reticle)
          if (Physics.Raycast(ray, distance, layer_mask)) //Only hit if Cube
          {
  
              //At the frame the screen is touched
              if (Input.GetMouseButtonDown(0))
              {
                  screenPoint = Camera.main.WorldToScreenPoint(gameObject.transform.position); //Where is the reticle in screen space?
                  offset = gameObject.transform.position - Camera.main.ScreenToWorldPoint(new Vector3(Input.mousePosition.x, Input.mousePosition.y, screenPoint.z)); //How far is the game object from reticle?
              }
  
              //Executed each frame whilst the screen is being touched
              if (Input.GetMouseButton(0))
              {
                  Vector3 cursorPoint = new Vector3(Input.mousePosition.x, Input.mousePosition.y, screenPoint.z);
                  Vector3 cursorPosition;
                  //Stop cube from moving outside boundary
                  cursorPosition.x = Mathf.Clamp(Camera.main.ScreenToWorldPoint(cursorPoint).x + offset.x, -4f, 4f);
                  cursorPosition.y = Mathf.Clamp(Camera.main.ScreenToWorldPoint(cursorPoint).y + offset.y, 0.5f, 4f);
                  cursorPosition.z = Mathf.Clamp(Camera.main.ScreenToWorldPoint(cursorPoint).z + offset.z, -4f, 4f);
                  gameObject.transform.position = cursorPosition; //Move cube to reticle position
                  GetComponent<Renderer>().material.color = Color.blue; //Change cube colour to blue
              }
          }
  
          //At the frame the touch is released
          if (Input.GetMouseButtonUp(0))
          {
              GetComponent<Renderer>().material.color = Color.red; //Change cube colour to red
              GameObject Cube1 = GameObject.FindWithTag("Cube1");
              GameObject Cube2 = GameObject.FindWithTag("Cube2");
              var dist = Vector3.Distance(Cube2.transform.position, Cube1.transform.position);
              var minDist = 2f;
  
              //Snap Cube to Position
              if (dist < minDist)
              {
                  Cube1.transform.position = Cube2.transform.position;
                  Cube1.transform.rotation = Cube2.transform.rotation;
                  GetComponent<Renderer>().material.color = Color.green;
              }
  
          }
      }
  }

Thanks for the help, I am very new to unity so sorry if the script is structured horribly or anything.