My Fixed Joint springs back to Zero.

Here's my code:

         // Start
         float xPosition = 10;
         float yPosition = 30;
         
         
         // While the whole length of rope
         while(ropeCount > 0 )
         {
             GameObject newRope;
             
             if(ropes.Count > 0)
             {
                 // create rope
                 newRope = (GameObject)Instantiate(ropePrefab);
                 newRope.transform.position = new Vector2(xPosition, yPosition);
                 
                 // attach rope
                 ((HingeJoint)newRope.GetComponent<HingeJoint>()).connectedBody = 
                     ((GameObject)ropes[ropes.Count - 1]).rigidbody;
             }
             else
             {    
                 // create hook
                 newRope = (GameObject)Instantiate(ropeHookPrefab);
                 newRope.transform.position = new Vector2(xPosition, yPosition);
             }
             
             ropes.Add(newRope);
         
             // move position
             xPosition += xMovement;
             yPosition += yMovement;
             
             ropeCount--;
         }

ropePrefab is a hinge joint object. ropeHookPrefab is a fixed joint object.

When I run this function all the objects line up exactly like they are supposed to. However, within two seconds the fixed joint pops back to position (0,0,0). No where in my code do I say move the fixed joint. Any idea what's going on?