### Godot version

4.0.2 stable

### System information

issue tested on win10 with ryzen 7 and rx 6600, win11 with ryzen 7 and gtx 3050

### Issue description

When creating a screen reading post processing shader, the normal buffer functions correctly in the editor, but does not seem to be functioning as expected in debug, producing only a solid colour when run. I am unsure if this behaviour is intended, but if so, I feel it should be properly documented.

Running correctly in editor:
![image](https://user-images.githubusercontent.com/71034402/230672620-fc5e4baf-c12e-4755-b7a2-206087459307.png)

Solid colour in debug:
![image](https://user-images.githubusercontent.com/71034402/230672489-d9c29755-c2d3-4e72-9ea0-355148e916fe.png)


### Steps to reproduce

*this shader should be attached to a MeshInstance3D quadmesh*
minimal shader to reproduce:

```glsl
shader_type spatial;
render_mode unshaded, cull_disabled;

uniform sampler2D NORMAL_TEXTURE : hint_normal_roughness_texture, filter_linear_mipmap;

void vertex(){
	VERTEX *= 2.0;
	POSITION = vec4(VERTEX, 1.0);
}

void fragment(){
	ALBEDO = texture(NORMAL_TEXTURE, SCREEN_UV).rgb;
}
```

### Minimal reproduction project

N/A
return (1 << RS::INSTANCE_VOXEL_GI);
}
void RenderForwardClustered::GeometryInstanceForwardClustered::pair_voxel_gi_instances(const RID *p_voxel_gi_instances, uint32_t p_voxel_gi_instance_count) {
	if (p_voxel_gi_instance_count > 0) {
		voxel_gi_instances[0] = p_voxel_gi_instances[0];
	} else {
		voxel_gi_instances[0] = RID();
	}
	if (p_voxel_gi_instance_count > 1) {
		voxel_gi_instances[1] = p_voxel_gi_instances[1];
	} else {
		voxel_gi_instances[1] = RID();
	}
}
void RenderForwardClustered::GeometryInstanceForwardClustered::set_softshadow_projector_pairing(bool p_softshadow, bool p_projector) {
	using_projectors = p_projector;
	using_softshadows = p_softshadow;
	_mark_dirty();
}
void RenderForwardClustered::_update_shader_quality_settings() {