### 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
AABB bounds;
	Vector3i from;
	Vector3i size;
	Ref<RenderSceneBuffersRD> rb = p_render_buffers;
	ERR_FAIL_COND_V(rb.is_null(), -1);
	Ref<RendererRD::GI::SDFGI> sdfgi = rb->get_custom_data(RB_SCOPE_SDFGI);
	ERR_FAIL_COND_V(sdfgi.is_null(), -1);
	return sdfgi->get_pending_region_data(p_region, from, size, bounds);
}
void RenderForwardClustered::GeometryInstanceForwardClustered::_mark_dirty() {
	if (dirty_list_element.in_list()) {
		return;
	}
	
	GeometryInstanceSurfaceDataCache *surf = surface_caches;
	while (surf) {
		GeometryInstanceSurfaceDataCache *next = surf->next;
		RenderForwardClustered::get_singleton()->geometry_instance_surface_alloc.free(surf);
		surf = next;
	}
	surface_caches = nullptr;
	RenderForwardClustered::get_singleton()->geometry_instance_dirty_list.add(&dirty_list_element);
}
void RenderForwardClustered::_geometry_instance_add_surface_with_material(GeometryInstanceForwardClustered *ginstance, uint32_t p_surface, SceneShaderForwardClustered::MaterialData *p_material, uint32_t p_material_id, uint32_t p_shader_id, RID p_mesh) {