Network transform jittering on client side with FixedUpdate and Cinemachine FixedUpdate

Hi, I am creating a multiplayer platformer, and i use Mirror for the networking and Unity 2020.3.48

I just want for example to move a cube and sync is position to all clients.

I use FixedUpdate() to move player and also to move the cube.
My cube have just a script with a basic Network transform, the movement is driving by server. (No client authority).

But when i move the player on client side i see the cube jittering ? On server side / host side no jittering. I really don't understand why ?

I recreate a minimalist project for testing this issue.

My Code for moving the cube :

Code (CSharp):

1. using System.Collections;
2. using System.Collections.Generic;
3. using UnityEngine;
4. using Mirror;
5.  
6. public class TestMoveNetwork : NetworkBehaviour
7. {
8.  
9.     public float TimeBeforeGoToOtherDirection;
10.     public float TimePassed;
11.  
12.     public Vector3 direction;
13.  
14.     public Rigidbody rb;
15.  
16.     private void Awake() {
17.         this.rb = GetComponent<Rigidbody>();
18.     }
19.  
20.     void Start() {
21.  
22.         direction = Vector3.left;
23.  
24.         TimeBeforeGoToOtherDirection = 3f;
25.         TimePassed = 0f;
26.     }
27.  
28.     void Update() {
29.  
30.     }
31.  
32.     private void FixedUpdate() {
33.  
34.         if(isServer) {
35.             simpleMove();
36.             //simpleMoveRigidbody();
37.         }
38.     }
39.  
40.     private void simpleMove() {
41.  
42.         float speed = 6f;
43.  
44.         TimePassed += Time.deltaTime;
45.         if(TimePassed >= this.TimeBeforeGoToOtherDirection) {
46.  
47.             TimePassed = 0f;
48.  
49.             direction = -direction;
50.         }
51.  
52.         Debug.Log(Time.deltaTime);
53.         Debug.Log(Time.fixedDeltaTime);
54.  
55.         transform.Translate(direction * Time.fixedDeltaTime * speed);
56.     }
57.  
58.     private void simpleMoveRigidbody() {
59.  
60.         float speed = 150f;
61.  
62.         TimePassed += Time.deltaTime;
63.         if(TimePassed >= this.TimeBeforeGoToOtherDirection) {
64.  
65.             TimePassed = 0f;
66.  
67.             direction = -direction;
68.             this.rb.velocity = Vector3.zero;
69.             this.rb.AddForce(direction * speed);
70.         }
71.     }
72. }

My code for moving the player :

Code (CSharp):

1. using System.Collections;
2. using System.Collections.Generic;
3. using UnityEngine;
4. using Mirror;
5. using Cinemachine;
6.  
7. [RequireComponent(typeof(CapsuleCollider))]
8. [RequireComponent(typeof(CharacterController))]
9. [RequireComponent(typeof(NetworkTransform))]
10. [RequireComponent(typeof(Rigidbody))]
11. public class PlayerControllerTest : NetworkBehaviour
12. {
13.     public CharacterController characterController;
14.  
15.     //public Camera OldMainCamera;
16.  
17.     [Header("Movement Settings")]
18.     public float moveSpeed = 8f;
19.     public float turnSensitivity = 5f;
20.     public float maxTurnSpeed = 100f;
21.  
22.     [Header("Diagnostics")]
23.     public float horizontal;
24.     public float vertical;
25.     public float turn;
26.     public float jumpSpeed;
27.     public bool isGrounded = true;
28.     public bool isFalling;
29.     public Vector3 velocity;
30.  
31.     void OnValidate()
32.     {
33.         if (characterController == null)
34.             characterController = GetComponent<CharacterController>();
35.  
36.         characterController.enabled = false;
37.         GetComponent<Rigidbody>().isKinematic = true;
38.         GetComponent<NetworkTransform>().clientAuthority = true;
39.         //OldMainCamera.enabled = false;
40.     }
41.  
42.     public override void OnStartLocalPlayer()
43.     {
44.         characterController.enabled = true;
45.         //OldMainCamera.enabled = true;
46.         GameManager._gameManagerInstance.thirdPersonVirtualCamera.GetComponent<CinemachineVirtualCamera>().Follow = this.transform;
47.     }
48.  
49.     void Update()
50.     {
51.         if (!isLocalPlayer || characterController == null || !characterController.enabled)
52.             return;
53.  
54.         horizontal = Input.GetAxis("Horizontal");
55.         vertical = Input.GetAxis("Vertical");
56.  
57.         // Q and E cancel each other out, reducing the turn to zero
58.         if (Input.GetKey(KeyCode.A))
59.             turn = Mathf.MoveTowards(turn, -maxTurnSpeed, turnSensitivity);
60.         if (Input.GetKey(KeyCode.E))
61.             turn = Mathf.MoveTowards(turn, maxTurnSpeed, turnSensitivity);
62.         if (Input.GetKey(KeyCode.A) && Input.GetKey(KeyCode.E))
63.             turn = Mathf.MoveTowards(turn, 0, turnSensitivity);
64.         if (!Input.GetKey(KeyCode.A) && !Input.GetKey(KeyCode.E))
65.             turn = Mathf.MoveTowards(turn, 0, turnSensitivity);
66.  
67.         if (isGrounded)
68.             isFalling = false;
69.  
70.         if ((isGrounded || !isFalling) && jumpSpeed < 1f && Input.GetKey(KeyCode.Space))
71.         {
72.             jumpSpeed = Mathf.Lerp(jumpSpeed, 1f, 0.5f);
73.         }
74.         else if (!isGrounded)
75.         {
76.             isFalling = true;
77.             jumpSpeed = 0;
78.         }
79.     }
80.  
81.     void FixedUpdate()
82.     {
83.         if (!isLocalPlayer || characterController == null || !characterController.enabled)
84.             return;
85.  
86.         transform.Rotate(0f, turn * Time.fixedDeltaTime, 0f);
87.  
88.         Vector3 direction = new Vector3(horizontal, jumpSpeed, vertical);
89.         direction = Vector3.ClampMagnitude(direction, 1f);
90.         direction = transform.TransformDirection(direction);
91.         direction *= moveSpeed;
92.  
93.         if (jumpSpeed > 0)
94.             characterController.Move(direction * Time.fixedDeltaTime);
95.         else
96.             characterController.SimpleMove(direction);
97.  
98.         isGrounded = characterController.isGrounded;
99.         velocity = characterController.velocity;
100.     }
101. }
102.  

My scene (Host Side)


NetworkTransform on Cube :


NetworkTransform on Player :


The cinemachine brain update mode and blend mode are on FixedUpdate()
Cinemachine virtual Camera use body 3rd person follow with on follow player transform :


The jittering on client (For this one i try this last version of Mirror) :