Instantiated prefab changes gravitational speed when dragged?

I have a simple scene with a basket case and a basket ball. I drag the basket ball using the mouse, and drop it whenever I get to the basket. The problem I am having is, that the longer the ball is dragged, the stronger is the gravitational force. This is a problem, and should stay consistent no matter for how long I drag the ball.

The basket ball gets instantiated when the game starts using the following lines of code:

 var basketBall : GameObject;
 
 function Start()
   {
              Instantiate(basketBall, Vector3(-7.669967,2.380085,0), Quaternion.identity);
   }
 
 function Update()
   {
   }

This script is applied to the camera in my scene.

The next script makes my ball prefab drag-able, and spawns a new ball whenever the previous one is dropped:

 using UnityEngine;
 using System.Collections;
 
 [RequireComponent(typeof(CircleCollider2D))]
 
 public class moveBall : MonoBehaviour
 {
     public GameObject Ball;
     void OnMouseDrag()
     {
         Vector3 point = Camera.main.ScreenToWorldPoint (Input.mousePosition);
         point.z = gameObject.transform.position.z;
         gameObject.transform.position = point;
         Screen.showCursor = false;
                 
     }
     
     void OnMouseUp()
     {
         Screen.showCursor = true;
         Instantiate(Ball, new Vector3(-7,2,0), Quaternion.Euler(0, 180, 0));
         print("Ball Dropped");
     }
 }

This script is applied to the ball prefab.

The Ball itself has a RigidBody 2D and a CircleCollider2D with a mass of 0.1 and a Physics 2D material with bounciness set to 0.6.

I have played a lot with the different parameters, but all produce the same bug (If it IS indeed a bug).