Interface glitch in background mode for WorldEnvironment

[KaruroChori]

Godot version:
Godot 4.0 bc30df8

OS/device including version:

Linux 80x86 64bit, GTX 1660 super and RTX 2060 (main one). Drivers 450.80

Issue description:
I am working in single window mode.
When setting the background mode for a WorldEnvironment node, canvas would result in what is shown in the attached figures.

Steps to reproduce:
Open the project and change the mode of the WorldEnvironment node.

Minimal reproduction project:
Attached


test-godot-4.zip

[Calinou]

OS: Fedora 33 (KDE + KWin)
GPU: GeForce GTX 1080 (NVIDIA 455.45.01)

Using single-window mode (which can be enabled in the Editor Settings). I'm not getting any error messages in the terminal when following the steps.

I can reproduce this on commit 90bdba5, albeit it looks different:

Window dialogs will also appear to be black:

It's worth nothing that I can't reproduce this on a brand new project though.

[Calinou]

Duplicate of #52467.