Shaders do not automatically inherit the default texture filter types from project settings, nor do they import image texture settings. about godot HOT 1 CLOSED

The project settings only create a default for CanvasItem textures, not for custom shaders. For custom shaders you always have to specify the filter and repeat settings that you want.

That being said, this particular bug was actually fixed a long time ago (in 4.0.1) Upgrading to any other version of Godot 4 will make the issue go away! In general we recommend users not stick to Godot 4.0-stable as it has many bugs that have long since been solved. I recommend using 4.2.2 if you can, or 4.04 if you prefer to stick to to the 4.0 major release.

from godot.