Mouse Clicks Stop After X# of clicks

Having an issue with mouse clicks which register when I first start a scene, but stop soon there after.

Set up:

2D project Sprite w/ 2D BoxCollider (Is Triggerable) Straightforward DO Something Script (At bottom)

Click #1 - All is well - new object created

Click #2 - All is well - new object created

Click #3 - All is well - new object created

Click #4 - All is well .

Click #5 - nothing... nothing and more nothing

I've tried using both OnMouse, and Update -> RayCast ... both with the same result, mouse clicks stop after a certain number of clicks.

Help would be appreciated, Many thanks.

Quick Note - Forgot to mention -- If while mouse is not working I go back into the unity editor and DELETE the first 4 Clones instantiated, I can click 4 more times... then it stops again. Rinse Repeat.

 /*
 void OnMouseDown()
 {
     
     if (Input.GetMouseButtonDown(0))
     {
         var newGO = (GameObject)Instantiate(Resources.Load("PreFabs/HorseCart")); ;
     }
     
 }
 */
 
 
 public void Update()
 {
     if (Input.GetMouseButtonDown(0))
     {
         Vector2 mousePosition = (Vector2)Camera.main.ScreenToWorldPoint(Input.mousePosition);
 
         RaycastHit2D hitCollider = Physics2D.Raycast(mousePosition, Vector2.zero, Mathf.Infinity);
 
 
         if (hitCollider && hitCollider.collider == ME)
         {
             var newGO = (GameObject)Instantiate(Resources.Load("PreFabs/HorseCart")); ;
         }
     }
 }