なぜかjointが複製されてしまう

ML-agentsでボール投げのAIを作っています。
最初はボールをくっつけてなんとかしてくれるのですが、２回目からjointが二つになってしまい、３回目以降からjointが４つになってしまうため、うまく動作ができません。
「なんとか複製されてしまうのを防げれば」光が見えるのですが、知識、ヒントをお持ちの方いないでしょうか。
今は手の3dラグドールの手の先端に、スフィアをくっつけて、-秒後に勝手に離れるので投げてくれ！という感じにしてます。
３回目に空中に固定されたボールに腕だけが接着し、最終的にラグドールがorzという形になって終わります。
至急答えてくれると幸いです。三回endepisodeが繰り返されてるのではないかという気がするのですが...

Walker agent.cs
using System;
using UnityEngine;
using Unity.MLAgents;
using Unity.MLAgents.Actuators;
using Unity.MLAgentsExamples;
using Unity.MLAgents.Sensors;
using BodyPart = Unity.MLAgentsExamples.BodyPart;
using Random = UnityEngine.Random;
[DisallowMultipleComponent]
public class WalkerAgent : Agent
{
public bool randomizeThrowSpeedEachEpisode;
private Vector3 m_WorldDirToThrow = Vector3.right;

[Header("Target To Throw Towards")] public Transform target;

[Header("Body Parts")] public Transform hips;
public Transform chest;
public Transform spine;
public Transform head;
public Transform thighL;
public Transform shinL;
public Transform footL;
public Transform thighR;
public Transform shinR;
public Transform footR;
public Transform armL;
public Transform forearmL;
public Transform handL;
public Transform armR;
public Transform forearmR;
public Transform handR;
OrientationCubeController m_OrientationCube;
DirectionIndicator m_DirectionIndicator;
JointDriveController m_JdController;
EnvironmentParameters m_ResetParams;
GameObject m_Sphere;
GameObject m_target;
GameObject hand_R;
Vector3 t_Sphere;
float byou;


public override void Initialize()
{
    m_OrientationCube = GetComponentInChildren<OrientationCubeController>();
    m_DirectionIndicator = GetComponentInChildren<DirectionIndicator>();
    m_Sphere = transform.Find("Sphere").gameObject;
    m_target = GameObject.Find("DynamicTarget");
    hand_R = transform.Find("hips/spine/chest/upper_arm_R/lower_arm_R/hand_R").gameObject;
    t_Sphere = m_Sphere.transform.localPosition;

    m_JdController = GetComponent<JointDriveController>();
    m_JdController.SetupBodyPart(hips);
    m_JdController.SetupBodyPart(chest);
    m_JdController.SetupBodyPart(spine);
    m_JdController.SetupBodyPart(head);
    m_JdController.SetupBodyPart(thighL);
    m_JdController.SetupBodyPart(shinL);
    m_JdController.SetupBodyPart(footL);
    m_JdController.SetupBodyPart(thighR);
    m_JdController.SetupBodyPart(shinR);
    m_JdController.SetupBodyPart(footR);
    m_JdController.SetupBodyPart(armL);
    m_JdController.SetupBodyPart(forearmL);
    m_JdController.SetupBodyPart(handL);
    m_JdController.SetupBodyPart(armR);
    m_JdController.SetupBodyPart(forearmR);
    m_JdController.SetupBodyPart(handR);

    m_ResetParams = Academy.Instance.EnvironmentParameters;

    SetResetParameters();
}

public override void OnEpisodeBegin()
{
    foreach (var bodyPart in m_JdController.bodyPartsDict.Values)
    {
        bodyPart.Reset(bodyPart);
    }

    byou = 0f;

    m_Sphere.transform.localPosition = t_Sphere;

    m_Sphere.gameObject.AddComponent<FixedJoint>();
    m_Sphere.gameObject.GetComponent<FixedJoint>().connectedBody = hand_R.gameObject.GetComponent<Rigidbody>();

    UpdateOrientationObjects();

    SetResetParameters();
}

public void CollectObservationBodyPart(BodyPart bp, VectorSensor sensor)
{
    sensor.AddObservation(bp.groundContact.touchingGround);
    sensor.AddObservation(m_OrientationCube.transform.InverseTransformDirection(bp.rb.velocity));
    sensor.AddObservation(m_OrientationCube.transform.InverseTransformDirection(bp.rb.velocity));
    sensor.AddObservation(m_OrientationCube.transform.InverseTransformDirection(bp.rb.angularVelocity)); 
    sensor.AddObservation(m_OrientationCube.transform.InverseTransformDirection(bp.rb.position - hips.position));

    if (bp.rb.transform != hips && bp.rb.transform != handL && bp.rb.transform != handR)
    {
        sensor.AddObservation(bp.rb.transform.localRotation);
        sensor.AddObservation(bp.currentStrength / m_JdController.maxJointForceLimit);
    }
}

public override void CollectObservations(VectorSensor sensor)
{
    var cubeForward = m_OrientationCube.transform.forward;

    //rotation deltas
    sensor.AddObservation(Quaternion.FromToRotation(hips.forward, cubeForward));
    sensor.AddObservation(Quaternion.FromToRotation(head.forward, cubeForward));

    sensor.AddObservation(m_OrientationCube.transform.InverseTransformPoint(target.transform.position));

    foreach (var bodyPart in m_JdController.bodyPartsList)
    {
        CollectObservationBodyPart(bodyPart, sensor);
    }
}

public override void OnActionReceived(ActionBuffers actionBuffers)

{
    var bpDict = m_JdController.bodyPartsDict;
    var i = -1;

    var continuousActions = actionBuffers.ContinuousActions;
    bpDict[chest].SetJointTargetRotation(continuousActions[++i], continuousActions[++i], continuousActions[++i]);
    bpDict[spine].SetJointTargetRotation(continuousActions[++i], continuousActions[++i], continuousActions[++i]);

    bpDict[thighL].SetJointTargetRotation(continuousActions[++i], continuousActions[++i], 0);
    bpDict[thighR].SetJointTargetRotation(continuousActions[++i], continuousActions[++i], 0);
    bpDict[shinL].SetJointTargetRotation(continuousActions[++i], 0, 0);
    bpDict[shinR].SetJointTargetRotation(continuousActions[++i], 0, 0);
    bpDict[footR].SetJointTargetRotation(continuousActions[++i], continuousActions[++i], continuousActions[++i]);
    bpDict[footL].SetJointTargetRotation(continuousActions[++i], continuousActions[++i], continuousActions[++i]);

    bpDict[armL].SetJointTargetRotation(continuousActions[++i], continuousActions[++i], 0);
    bpDict[armR].SetJointTargetRotation(continuousActions[++i], continuousActions[++i], 0);
    bpDict[forearmL].SetJointTargetRotation(continuousActions[++i], 0, 0);
    bpDict[forearmR].SetJointTargetRotation(continuousActions[++i], 0, 0);
    bpDict[head].SetJointTargetRotation(continuousActions[++i], continuousActions[++i], 0);

    //update joint strength settings
    bpDict[chest].SetJointStrength(continuousActions[++i]);
    bpDict[spine].SetJointStrength(continuousActions[++i]);
    bpDict[head].SetJointStrength(continuousActions[++i]);
    bpDict[thighL].SetJointStrength(continuousActions[++i]);
    bpDict[shinL].SetJointStrength(continuousActions[++i]);
    bpDict[footL].SetJointStrength(continuousActions[++i]);
    bpDict[thighR].SetJointStrength(continuousActions[++i]);
    bpDict[shinR].SetJointStrength(continuousActions[++i]);
    bpDict[footR].SetJointStrength(continuousActions[++i]);
    bpDict[armL].SetJointStrength(continuousActions[++i]);
    bpDict[forearmL].SetJointStrength(continuousActions[++i]);
    bpDict[armR].SetJointStrength(continuousActions[++i]);
    bpDict[forearmR].SetJointStrength(continuousActions[++i]);
}

void UpdateOrientationObjects()
{
    m_WorldDirToThrow = target.position - hips.position;
    m_OrientationCube.UpdateOrientation(hips, target);
    if (m_DirectionIndicator)
    {
        m_DirectionIndicator.MatchOrientation(m_OrientationCube.transform);
    }
}

void FixedUpdate()
{
    UpdateOrientationObjects();

    var cubeForward = m_OrientationCube.transform.forward;

    var lookAtTargetReward = (Vector3.Dot(cubeForward, head.forward) + 1) * .5F;

    if (float.IsNaN(lookAtTargetReward))
    {
        throw new ArgumentException(
            "NaN in lookAtTargetReward.\n" +
            $" cubeForward: {cubeForward}\n" +
            $" head.forward: {head.forward}"
        );
    }
    AddReward(lookAtTargetReward);

    byou += Time.deltaTime;
    Destroy(m_Sphere.gameObject.GetComponent<FixedJoint>(),1.0f);

    if(byou >= 4){
        if(m_Sphere.GetComponent<Rigidbody>().velocity==Vector3.zero){
            Vector3 posA = m_Sphere.transform.position;
            Vector3 posB = m_target.transform.position;
            float dis = Vector3.Distance(posA,posB);
            Vector3 posC = m_OrientationCube.transform.position;
            float kyori = Vector3.Distance(posC,posB);
            float res = kyori-dis;
            AddReward(res*0.01f);
            EndEpisode();
        }
    }
}

public void SetTorsoMass()
{
    m_JdController.bodyPartsDict[chest].rb.mass = m_ResetParams.GetWithDefault("chest_mass", 8);
    m_JdController.bodyPartsDict[spine].rb.mass = m_ResetParams.GetWithDefault("spine_mass", 8);
    m_JdController.bodyPartsDict[hips].rb.mass = m_ResetParams.GetWithDefault("hip_mass", 8);
}

public void SetResetParameters()
{
    SetTorsoMass();
}