Repository: godot
Issue: Multiple MultiplayerSynchronizer's under MultiplayerSpawner with different public_visibility states prints error
Labels: discussion,topic:network

### Godot version

v4.0.beta.custom_build [f814e15c7] (built after alpha 4)

### System information

Linux 5.15.76-1-MANJARO x86_64 GNU/Linux --- Vulkan API 1.2.0 - Using Vulkan Device #1: Intel - Intel(R) UHD Graphics 620 (KBL GT2)

### Issue description

I am setting up an authoritative server/client real-time strategy game using MultiplayerSpawner and MultiplayerSynchronizer. My player scene has several properties that need synchronized to the clients. My player scene also has a 'module' system for easily bolting on functionality to a player. These player modules also have several properties that need synchronized with clients. My first thought was to add a MultiplayerSynchronizer to the player module, so I wouldn't have to pass a reference to the player's synchronizer into the module. That's when I came across these errors.

With a player structure as shown in the images below. 
![image](https://user-images.githubusercontent.com/12703200/201278115-ed647d46-5a2e-4a33-aa0f-3a84f52d34ca.png)
![image](https://user-images.githubusercontent.com/12703200/201281064-7b14a9fa-00e8-41ac-9f84-1b01c9c6b9b6.png)
![image](https://user-images.githubusercontent.com/12703200/201281120-d889449a-d8fb-4d94-8011-b2a931e7e884.png)

These errors are printed to Godot's console after a client connects:
```
E 0:00:00:0483   get_node: Node not found: "World/MultiplayerSpawner/Player/Nested/PublicVisibilityOn" (relative to "/root/Main/Client").
  <C++ Error>    Method/function failed. Returning: nullptr
  <C++ Source>   scene/main/node.cpp:1360 @ get_node()

E 0:00:00:0483   process_simplify_path: Condition "node == nullptr" is true.
  <C++ Source>   modules/multiplayer/scene_cache_interface.cpp:77 @ process_simplify_path()
```

Also, when swapping out the "Nested" node with a "Gun" node containing a MultiplayerSpawner which spawns bullets containing a MultiplayerSynchronizer, I get the errors below.

![image](https://user-images.githubusercontent.com/12703200/201282312-02451ce0-3ed5-4389-bf2a-771a9e560e40.png)
![image](https://user-images.githubusercontent.com/12703200/201283529-0f72e5e5-55a6-4c16-bd52-793acbd2ebe0.png)


```
E 0:00:00:0450   get_node: Node not found: "World/MultiplayerSpawner/Player/Gun/BulletSpawner" (relative to "/root/Main/Client").
  <C++ Error>    Method/function failed. Returning: nullptr
  <C++ Source>   scene/main/node.cpp:1360 @ get_node()

E 0:00:00:0450   process_simplify_path: Condition "node == nullptr" is true.
  <C++ Source>   modules/multiplayer/scene_cache_interface.cpp:77 @ process_simplify_path()

E 0:00:00:0450   get_cached_object: ID 1 not found in cache of peer 1.
  <C++ Error>    Condition "!F" is true. Returning: nullptr
  <C++ Source>   modules/multiplayer/scene_cache_interface.cpp:249 @ get_cached_object()

E 0:00:00:0450   on_spawn_receive: Condition "!spawner" is true. Returning: ERR_DOES_NOT_EXIST
  <C++ Source>   modules/multiplayer/scene_replication_interface.cpp:484 @ on_spawn_receive()
```

I get the feeling that I am using MultiplayerSpawner and MultiplayerSynchronizer incorrectly. That I should not nest MultiplayerSpawners and not have more than one MultiplayerSynchronizer in a spawned scene.

Perhaps the error messages could be improved to help users better understand what they are doing wrong? Or add documentation to suggest the intended node structure usage?

### Steps to reproduce

See minimal reproduction project for details, but here are screenshots of the final remote node structure after running the attached demos.

Final running scene tree:
![image](https://user-images.githubusercontent.com/12703200/201239777-fa15f969-0f78-47ca-b4b0-3a8a3103002e.png)

Final running scene tree with nested bullet spawner:
![image](https://user-images.githubusercontent.com/12703200/201281533-f3c72467-c1c6-4f85-aaf7-7293ffd1173b.png)



### Minimal reproduction project

[problem_demo_multiplayer_spawn_sync_gd4.zip](https://github.com/godotengine/godot/files/9985666/problem_demo_multiplayer_spawn_sync_gd4.zip)

[problem_demo_multiplayer_spawn_sync_gd4_bullet_spawner.zip](https://github.com/godotengine/godot/files/9987468/problem_demo_multiplayer_spawn_sync_gd4_bullet_spawner.zip)