### 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
}
				}
			}
			ginstance->instance_count = particles_storage->particles_get_amount(ginstance->data->base, ginstance->trail_steps);
		} break;
		default: {
		}
	}
	
	ginstance->base_flags = 0;
	bool store_transform = true;
	if (ginstance->data->base_type == RS::INSTANCE_MULTIMESH) {
		ginstance->base_flags |= INSTANCE_DATA_FLAG_MULTIMESH;
		if (mesh_storage->multimesh_get_transform_format(ginstance->data->base) == RS::MULTIMESH_TRANSFORM_2D) {
			ginstance->base_flags |= INSTANCE_DATA_FLAG_MULTIMESH_FORMAT_2D;
		}
		if (mesh_storage->multimesh_uses_colors(ginstance->data->base)) {
			ginstance->base_flags |= INSTANCE_DATA_FLAG_MULTIMESH_HAS_COLOR;
		}
		if (mesh_storage->multimesh_uses_custom_data(ginstance->data->base)) {
			ginstance->base_flags |= INSTANCE_DATA_FLAG_MULTIMESH_HAS_CUSTOM_DATA;
		}
		ginstance->transforms_uniform_set = mesh_storage->multimesh_get_3d_uniform_set(ginstance->data->base, scene_shader.default_shader_rd, TRANSFORMS_UNIFORM_SET);
	} else if (ginstance->data->base_type == RS::INSTANCE_PARTICLES) {
		ginstance->base_flags |= INSTANCE_DATA_FLAG_PARTICLES;
		ginstance->base_flags |= INSTANCE_DATA_FLAG_MULTIMESH;
		ginstance->base_flags |= INSTANCE_DATA_FLAG_MULTIMESH_HAS_COLOR;
		ginstance->base_flags |= INSTANCE_DATA_FLAG_MULTIMESH_HAS_CUSTOM_DATA;
		
		ginstance->base_flags |= (ginstance->trail_steps << INSTANCE_DATA_FLAGS_PARTICLE_TRAIL_SHIFT);