`NetworkObject` `CheckObjectVisibility` doesn't work on client connection

Description

I want to spawn a networkprefab without any client visibility, first i tried to set no observers before spawn:

NetworkObject.SpawnWithObservers = false;
NetworkObject.Spawn();

this results a spawned object with zero observers, but when a late-join client connects, the object gets spawned on client. The documentation says this is the intended normal behavior, because it only works at the initial spawning.

Then, the documentation says the CheckObjectVisibility will work at both initial spawning and new client connection, so i tried this:

NetworkObject.CheckObjectVisibility += _ => false;
NetworkObject.Spawn();

it did spawn with no observers as the previous approach, but when late-join client connects, it still spawn the object on client.

Reproduce Steps

1. start server/host
2. spawn a network prefab with NetworkObject.CheckObjectVisibility += _ => false;
3. start a client and connect to server

Actual Outcome

a spawned object with visibility always set to false still spawns on late-join client

Expected Outcome

a spawned object with visibility always set to false should be invisible to all connected client and future late-join clients

Environment

• OS: [win10]
• Unity Version: [6000.0.32f1]
• Netcode Version: [2.1.1]

从 NetworkObject 的 SpawnWithObservers、Spawn 和 CheckObjectVisibility 行为入手，对比报告中链接的 spawning 和对象可见性文档。复现 CheckObjectVisibility 返回 false 时的 late-join 序列，并确认对象在客户端上仍然不存在；完成标准是可见性也会对未来 late-join 的客户端生效。