quality-control/Assets/Scripts/Machines/ProductReceiver.cs

using System.Collections;
using System.Collections.Generic;
using UnityEngine;

public class ProductReceiver : MonoBehaviour
{
    ///HashSet<Rigidbody> enteredBodies = new HashSet<Rigidbody>();

    public int normalProductCount;
    public int defectiveProductCount;

    private void OnCollisionEnter(Collision collision)
    {
        var rb = collision.rigidbody;

        if (!rb)
        {
            return;
        }
        
        //enteredBodies.Add(rb);
            
        if (rb.GetComponent<DefectiveProduct>())
        {
            defectiveProductCount++;
        }
        else
        {
            normalProductCount++;
        }
            
        Destroy(rb.gameObject);
    }
}