### 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
RENDER_TIMESTAMP("Setup Rendering UV2");
	RD::get_singleton()->draw_command_begin_label("Render UV2");
	RenderSceneDataRD scene_data;
	scene_data.dual_paraboloid_side = 0;
	scene_data.material_uv2_mode = true;
	scene_data.opaque_prepass_threshold = 0.0;
	scene_data.emissive_exposure_normalization = -1.0;
	RenderDataRD render_data;
	render_data.scene_data = &scene_data;
	render_data.cluster_size = 1;
	render_data.cluster_max_elements = 32;
	render_data.instances = &p_instances;
	_update_render_base_uniform_set();
	_setup_environment(&render_data, true, Vector2(1, 1), false, Color());
	PassMode pass_mode = PASS_MODE_DEPTH_MATERIAL;
	_fill_render_list(RENDER_LIST_SECONDARY, &render_data, pass_mode);
	render_list[RENDER_LIST_SECONDARY].sort_by_key();
	_fill_instance_data(RENDER_LIST_SECONDARY);
	RID rp_uniform_set = _setup_render_pass_uniform_set(RENDER_LIST_SECONDARY, nullptr, RID());
	RENDER_TIMESTAMP("Render 3D Material");
	{
		RenderListParameters render_list_params(render_list[RENDER_LIST_SECONDARY].elements.ptr(), render_list[RENDER_LIST_SECONDARY].element_info.ptr(), render_list[RENDER_LIST_SECONDARY].elements.size(), true, pass_mode, 0, true, false, rp_uniform_set, true);
		
		Vector<Color> clear = {
			Color(0, 0, 0, 0),
			Color(0, 0, 0, 0),
			Color(0, 0, 0, 0),
			Color(0, 0, 0, 0),