Why does AddExplosionForce() not apply force to clients? (UNet)

Hey Folks,

I got a sphere which has a collider, rigidbody and the following script attached to it.

     using UnityEngine;
     using UnityEngine.Networking;
     using System.Collections;
     
     public class PhysicsTest: NetworkBehaviour
     {
         int playerMask;
     
         [SerializeField] float[] explosionRadius = 5f;
         [SerializeField] float[] explosionForce = 1000f;
         [SerializeField] AudioSource ambienceAudio;
 
         private void Start()
         {
             if (isServer)
                 ambienceAudio.Play();
             playerMask = LayerMask.GetMask("Player");
         }
     
         [ServerCallback]
         private void OnCollisionEnter(Collision c)
         {
             if(c.gameObject.tag == "Player")
             {    
                 ApplyPhysics(explosionForce, explosionRadius);
                 NetworkServer.Destroy(gameObject);
             }
         }
     
         [ServerCallback]
         private void ApplyPhysics(float force, float radius)
         {
             Collider[] players = Physics.OverlapSphere(transform.position, radius, playerMask);
     
             foreach (Collider targets in players)
             {
                 Rigidbody playerRB = targets.GetComponent<Rigidbody>();
                 targets.AddExplosionForce(force, transform.position, radius);
             }
         }
 }

This applies force to the server only. However, If I call ApplyPhsics via OnNetworkDestroy it works somehow for both, the server and the client(s).

 public override void OnNetworkDestroy()
 {
         ApplyPhysics(explosionForce, explosionRadius);
         base.OnNetworkDestroy ();
 }

Can anyone explain to me why it behaves like this? What do I have to do to make this work without OnNetworkDestroy() ?

Thank you very much in advance for your input!

Dominik