UNET (Multiplayer) calling [command] function twice

I am playing around with UNET but stuck into this weird problem/scenario while testing on same machine (unityEditor and buildRun to create "2 players/instances"

The problem is weird interaction of [Command] attribute and void OnStartLocalPlayer() when hosting the game in Editor's instance and in standalonePlayer instance

1. Basically, when I am host in editorInstance (host), the function associated with [Command] is triggered twice by the standaloneInstance (client)
   

2. When I am hosting in standaloneInstance (host), the line which calls the function associated with [Command] throws warning "Trying to send command for object without authority." But the function works as expected

I am spawning a PlayerObject from my NetworkLobbyManager and then that PlayerObject spawns its own pieces (sub-objects) using NetworkServer.Spawn(playerUnit);

Any help would be appreciated :( I like learning by trial and error but since 3 days I have not progressed or understood whats going on.

 using System.Collections;
 using System.Collections.Generic;
 using UnityEngine;
 using UnityEngine.Networking;
 
 public class playerManager : NetworkBehaviour
 {
     public int playerID;
     public GameController GC;
     public int playerUnitID;
     public bool localPlayer;
     public bool serverPlayer;
     public bool clientPlayer;
 
     // Use this for initialization
     void Start () {
         //Assign player unique ID as per order of joining
         if (!GC)
         {
             GC = GameObject.FindObjectOfType<GameController>();
             //playerID = this.GetComponent<NetworkIdentity>().connectionToClient.connectionId; connectionToClient is for serverOnly, connectionToServer is clientOnly
             playerID = (int)netId.Value;
             Debug.Log("(PM) Created GC in Start: " + playerID);
             //CmdCreatePlayerUnit(playerID);        //this gets called in OnStartLocalPlayer anyway(Trying to send command for object without authority)
         }
         localPlayer = isLocalPlayer;
         serverPlayer = isServer;
         clientPlayer = isClient;
 
         Debug.Log("Player: "+playerID+" isLocalPlayer: "+localPlayer+" and isServerPlayer: "+serverPlayer);
     }
     
     // Update is called once per frame
     void Update () {
         
     }
 
     public override void OnStartLocalPlayer()
     {
         if (!GC)
         {
             GC = GameObject.FindObjectOfType<GameController>();
             //playerID = this.GetComponent<NetworkIdentity>().connectionToClient.connectionId; connectionToClient is for serverOnly, connectionToServer is clientOnly
             playerID = (int)netId.Value;
             Debug.Log("(PM) Created GC in OnStartLocalPlayer: " + playerID);
             CmdCreatePlayerUnit(playerID);
         }
         //Debug.Log("(PM) OnStartLocalPlayer: " + gameObject.name);
         Debug.Log("Player: " + playerID + " isLocalPlayer: " + localPlayer + " and isServerPlayer: " + serverPlayer);
     }
 
     [Command]
     void CmdCreatePlayerUnit(int playerID)
     {
         Debug.Log("Creating player unit with ID: " + playerID + " and isLocalPlayer: "+isLocalPlayer);
         GC.registerPlayerNetID(playerID);
         Debug.Log("(PM) Registered Players: " + GC.playerNetIDs.Count);
         for (int i = 0; i < GC.playerNetIDs.Count; i++)
         {
             //Debug.Log(GC.playerNetIDs[i]);
             if(GC.playerNetIDs[i]==playerID)
             {
                 playerUnitID = i;
                 Debug.Log(playerID+" player's unitID is "+i);
             }
         }
         GameObject prefab = GC.players[playerUnitID];
         GameObject playerUnit = (GameObject)Instantiate(prefab, prefab.transform.position, prefab.transform.rotation);
         NetworkServer.Spawn(playerUnit);
 
         //Update the same in GC
         GC.registerPlayer1(playerUnit,(int)playerUnitID);
     }
 
 
 
      
 
 
 }