### 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
static const uint32_t divisor[RS::PRIMITIVE_MAX] = { 1, 2, 1, 3, 1 };
	static const uint32_t subtractor[RS::PRIMITIVE_MAX] = { 0, 0, 1, 0, 1 };
	return (p_indices - subtractor[p_primitive]) / divisor[p_primitive];
}
void RenderForwardClustered::_fill_render_list(RenderListType p_render_list, const RenderDataRD *p_render_data, PassMode p_pass_mode, uint32_t p_color_pass_flags = 0, bool p_using_sdfgi, bool p_using_opaque_gi, bool p_append) {
	RendererRD::MeshStorage *mesh_storage = RendererRD::MeshStorage::get_singleton();
	if (p_render_list == RENDER_LIST_OPAQUE) {
		scene_state.used_sss = false;
		scene_state.used_screen_texture = false;
		scene_state.used_normal_texture = false;
		scene_state.used_depth_texture = false;
	}
	uint32_t lightmap_captures_used = 0;
	Plane near_plane = Plane(-p_render_data->scene_data->cam_transform.basis.get_column(Vector3::AXIS_Z), p_render_data->scene_data->cam_transform.origin);
	near_plane.d += p_render_data->scene_data->cam_projection.get_z_near();
	float z_max = p_render_data->scene_data->cam_projection.get_z_far() - p_render_data->scene_data->cam_projection.get_z_near();
	RenderList *rl = &render_list[p_render_list];
	_update_dirty_geometry_instances();
	if (!p_append) {
		rl->clear();
		if (p_render_list == RENDER_LIST_OPAQUE) {
			render_list[RENDER_LIST_ALPHA].clear(); 
		}
	}