### 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
RS::InstanceType type = RSG::utilities->get_base_type(p_base);
	ERR_FAIL_COND_V(!((1 << type) & RS::INSTANCE_GEOMETRY_MASK), nullptr);
	GeometryInstanceForwardClustered *ginstance = geometry_instance_alloc.alloc();
	ginstance->data = memnew(GeometryInstanceForwardClustered::Data);
	ginstance->data->base = p_base;
	ginstance->data->base_type = type;
	ginstance->data->dependency_tracker.userdata = ginstance;
	ginstance->data->dependency_tracker.changed_callback = _geometry_instance_dependency_changed;
	ginstance->data->dependency_tracker.deleted_callback = _geometry_instance_dependency_deleted;
	ginstance->_mark_dirty();
	return ginstance;
}
void RenderForwardClustered::GeometryInstanceForwardClustered::set_transform(const Transform3D &p_transform, const AABB &p_aabb, const AABB &p_transformed_aabbb) {
	uint64_t frame = RSG::rasterizer->get_frame_number();
	if (frame != prev_transform_change_frame) {
		prev_transform = transform;
		prev_transform_change_frame = frame;
		prev_transform_dirty = true;
	}
	RenderGeometryInstanceBase::set_transform(p_transform, p_aabb, p_transformed_aabbb);
}
void RenderForwardClustered::GeometryInstanceForwardClustered::set_use_lightmap(RID p_lightmap_instance, const Rect2 &p_lightmap_uv_scale, int p_lightmap_slice_index) {
	lightmap_instance = p_lightmap_instance;
	lightmap_uv_scale = p_lightmap_uv_scale;
	lightmap_slice_index = p_lightmap_slice_index;
	_mark_dirty();
}
void RenderForwardClustered::GeometryInstanceForwardClustered::set_lightmap_capture(const Color *p_sh9) {