Environment difference between directly starting a scene and loading scene

[guoboism]

Godot version

Godot_v4.1.1-stable_mono_win64

System information

Win11 forward+

Issue description

With the same scene with some environment setting, the background color is different between:
A: directly start with the scene
B: load into the scene in runtime from another scene

A

B

Steps to reproduce

1 Use provided project
2 Open game.tscn and directly start from this scene
3 Notice the background color (blue)
4 Start the project, click "start game" to load game.tscn
5 Notice the background color (black)

Minimal reproduction project

GDTetris.zip

[guoboism]

Related to #80889 ?