### 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
depth_framebuffer = light_storage->reflection_probe_instance_get_depth_framebuffer(p_render_data->reflection_probe, p_render_data->reflection_probe_pass);
		if (light_storage->reflection_probe_is_interior(light_storage->reflection_probe_instance_get_probe(p_render_data->reflection_probe))) {
			p_render_data->environment = RID(); 
		}
		reverse_cull = true; 
	} else {
		screen_size = rb->get_internal_size();
		if (rb->get_use_taa() || get_debug_draw_mode() == RS::VIEWPORT_DEBUG_DRAW_MOTION_VECTORS) {
			color_pass_flags |= COLOR_PASS_FLAG_MOTION_VECTORS;
		}
		if (p_render_data->voxel_gi_instances->size() > 0) {
			using_voxelgi = true;
		}
		if (p_render_data->environment.is_valid()) {
			if (environment_get_sdfgi_enabled(p_render_data->environment)) {
				using_sdfgi = true;
			}
			if (environment_get_ssr_enabled(p_render_data->environment)) {
				using_separate_specular = true;
				using_ssr = true;
				color_pass_flags |= COLOR_PASS_FLAG_SEPARATE_SPECULAR;
			}
		}
		if (p_render_data->scene_data->view_count > 1) {
			color_pass_flags |= COLOR_PASS_FLAG_MULTIVIEW;
		}
		color_framebuffer = rb_data->get_color_pass_fb(color_pass_flags);
		color_only_framebuffer = rb_data->get_color_only_fb();
	}
	p_render_data->scene_data->emissive_exposure_normalization = -1.0;