### 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
RendererRD::LightStorage *light_storage = RendererRD::LightStorage::get_singleton();
	scene_state.lightmaps_used = 0;
	for (int i = 0; i < (int)p_lightmaps.size(); i++) {
		if (i >= (int)scene_state.max_lightmaps) {
			break;
		}
		RID lightmap = light_storage->lightmap_instance_get_lightmap(p_lightmaps[i]);
		Basis to_lm = light_storage->lightmap_instance_get_transform(p_lightmaps[i]).basis.inverse() * p_cam_transform.basis;
		to_lm = to_lm.inverse().transposed(); 
		RendererRD::MaterialStorage::store_transform_3x3(to_lm, scene_state.lightmaps[i].normal_xform);
		scene_state.lightmaps[i].exposure_normalization = 1.0;
		if (p_render_data->camera_attributes.is_valid()) {
			float baked_exposure = light_storage->lightmap_get_baked_exposure_normalization(lightmap);
			float enf = RSG::camera_attributes->camera_attributes_get_exposure_normalization_factor(p_render_data->camera_attributes);
			scene_state.lightmaps[i].exposure_normalization = enf / baked_exposure;
		}
		scene_state.lightmap_ids[i] = p_lightmaps[i];
		scene_state.lightmap_has_sh[i] = light_storage->lightmap_uses_spherical_harmonics(lightmap);
		scene_state.lightmaps_used++;
	}
	if (scene_state.lightmaps_used > 0) {
		RD::get_singleton()->buffer_update(scene_state.lightmap_buffer, 0, sizeof(LightmapData) * scene_state.lightmaps_used, scene_state.lightmaps, RD::BARRIER_MASK_RASTER);
	}
}
void RenderForwardClustered::_update_sdfgi(RenderDataRD *p_render_data) {