fix

Send InSceneNetworkObjectsSpawned and InternalNetworkSessionSynchronized NetworkBehaviour notifications on the server, host, and session owner side when first starting a session.

Author: NoelStephensUnity

com.unity.netcode.gameobjects/Runtime/Core/NetworkManager.cs

@@ -1218,6 +1218,17 @@ public bool StartServer()
                 {
                     SpawnManager.ServerSpawnSceneObjectsOnStartSweep();
 
+                    // Notify the server that all in-scnee placed NetworkObjects are spawned at this time.
+                    foreach (var networkObject in SpawnManager.SpawnedObjectsList)
+                    {
+                        networkObject.InternalInSceneNetworkObjectsSpawned();
+                    }
+
+                    // Notify the server that everything should be synchronized/spawned at this time.
+                    foreach (var networkObject in SpawnManager.SpawnedObjectsList)
+                    {
+                        networkObject.InternalNetworkSessionSynchronized();
+                    }
                     OnServerStarted?.Invoke();
                     ConnectionManager.LocalClient.IsApproved = true;
                     return true;
@@ -1364,6 +1375,17 @@ private void HostServerInitialize()
             }
 
             SpawnManager.ServerSpawnSceneObjectsOnStartSweep();
+            // Notify the host that all in-scnee placed NetworkObjects are spawned at this time.
+            foreach (var networkObject in SpawnManager.SpawnedObjectsList)
+            {
+                networkObject.InternalInSceneNetworkObjectsSpawned();
+            }
+
+            // Notify the host that everything should be synchronized/spawned at this time.
+            foreach (var networkObject in SpawnManager.SpawnedObjectsList)
+            {
+                networkObject.InternalNetworkSessionSynchronized();
+            }
 
             OnServerStarted?.Invoke();
             OnClientStarted?.Invoke();

com.unity.netcode.gameobjects/Runtime/Messaging/Messages/ConnectionApprovedMessage.cs

@@ -243,6 +243,13 @@ public void Handle(ref NetworkContext context)
                         // Spawn any in-scene placed NetworkObjects
                         networkManager.SpawnManager.ServerSpawnSceneObjectsOnStartSweep();
 
+                        // With scene management enabled and since the session owner doesn't send a Synchronize scene event synchronize itself,
+                        // we need to notify the session owner that all in-scnee placed NetworkObjects are spawned at this time.
+                        foreach (var networkObject in networkManager.SpawnManager.SpawnedObjectsList)
+                        {
+                            networkObject.InternalInSceneNetworkObjectsSpawned();
+                        }
+
                         // Spawn the local player of the session owner
                         if (networkManager.AutoSpawnPlayerPrefabClientSide)
                         {
@@ -252,6 +259,13 @@ public void Handle(ref NetworkContext context)
                         // Synchronize the service with the initial session owner's loaded scenes and spawned objects
                         networkManager.SceneManager.SynchronizeNetworkObjects(NetworkManager.ServerClientId);
 
+                        // With scene management enabled and since the session owner doesn't send a Synchronize scene event synchronize itself,
+                        // we need to notify the session owner that everything should be synchronized/spawned at this time.
+                        foreach (var networkObject in networkManager.SpawnManager.SpawnedObjectsList)
+                        {
+                            networkObject.InternalNetworkSessionSynchronized();
+                        }
+
                         // When scene management is enabled and since the session owner is synchronizing the service (i.e. acting like  host),
                         // we need to locallyh invoke the OnClientConnected callback at this point in time.
                         networkManager.ConnectionManager.InvokeOnClientConnectedCallback(OwnerClientId);