### 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
} else {
					if (p_using_sdfgi && inst->can_sdfgi) {
						flags |= INSTANCE_DATA_FLAG_USE_SDFGI;
						uses_gi = true;
					}
					inst->gi_offset_cache = 0xFFFFFFFF;
				}
			}
		}
		inst->flags_cache = flags;
		GeometryInstanceSurfaceDataCache *surf = inst->surface_caches;
		while (surf) {
			surf->sort.uses_forward_gi = 0;
			surf->sort.uses_lightmap = 0;
			
			if (p_render_data->scene_data->screen_mesh_lod_threshold > 0.0 && mesh_storage->mesh_surface_has_lod(surf->surface)) {
				
				Vector3 lod_support_min = inst->transformed_aabb.get_support(p_render_data->scene_data->cam_transform.basis.get_column(Vector3::AXIS_Z));
				Vector3 lod_support_max = inst->transformed_aabb.get_support(-p_render_data->scene_data->cam_transform.basis.get_column(Vector3::AXIS_Z));
				
				float distance_min = (float)p_render_data->scene_data->cam_transform.origin.distance_to(lod_support_min);
				float distance_max = (float)p_render_data->scene_data->cam_transform.origin.distance_to(lod_support_max);
				float distance = 0.0;
				if (distance_min * distance_max < 0.0) {
					
					distance = 0.0;
				} else if (distance_min >= 0.0) {
					distance = distance_min;
				} else if (distance_max <= 0.0) {
					distance = -distance_max;