Raycast ignoring GameObjects on Maximize

So, I've been having various issues with an RTS-like unit selection system, where you click an unit to select it, and if you click the ground all units are deselected; after almost two hours testing stuff and trying to solve bugs I found that there's only one problem, and it only occurs on when the game window is on maximize. Basically, after a few seconds (something like 4.8 seconds to be more precise) the Raycast starts ignoring collision with some GameObjects (the player units, in this case)

 public GameObject selectedObject;
 public ObjectInfo selectedInfo;
 
 public void LeftClick()
     {
         Ray ray = Camera.main.ScreenPointToRay(Input.mousePosition);
         RaycastHit hit;
 
         if (Physics.Raycast(ray, out hit))
         {
             if (hit.collider.tag == "Ground")
             {
                 selectedObject = null;
 //deselect both units when clicking on ground
                 GameObject.Find("Hero").GetComponent<ObjectInfo>().isSelected = false;
                 GameObject.Find("Builder").GetComponent<ObjectInfo>().isSelected = false;
                 Debug.Log("Deselected");
             }
             if (hit.collider.tag == "Selectable")
             {
                 selectedObject = hit.collider.gameObject;
                 selectedInfo = selectedObject.GetComponent<ObjectInfo>();
                 selectedInfo.isSelected = true; //this variable is used to determine wheter the unit can move or not in another script
                 Debug.Log("Selected " + selectedInfo.objectName);
             }
         }
     }