### 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
scene_state.ubo.volumetric_fog_detail_spread = 1.0 / fog_detail_spread;
			} else {
				scene_state.ubo.volumetric_fog_detail_spread = 1.0;
			}
		}
	}
	if (get_debug_draw_mode() == RS::VIEWPORT_DEBUG_DRAW_UNSHADED) {
		scene_state.ubo.ss_effects_flags = 0;
	} else if (p_render_data->reflection_probe.is_null() && is_environment(p_render_data->environment)) {
		scene_state.ubo.ssao_ao_affect = environment_get_ssao_ao_channel_affect(p_render_data->environment);
		scene_state.ubo.ssao_light_affect = environment_get_ssao_direct_light_affect(p_render_data->environment);
		uint32_t ss_flags = 0;
		if (p_opaque_render_buffers) {
			ss_flags |= environment_get_ssao_enabled(p_render_data->environment) ? 1 : 0;
			ss_flags |= environment_get_ssil_enabled(p_render_data->environment) ? 2 : 0;
		}
		scene_state.ubo.ss_effects_flags = ss_flags;
	} else {
		scene_state.ubo.ss_effects_flags = 0;
	}
	if (p_index >= (int)scene_state.implementation_uniform_buffers.size()) {
		uint32_t from = scene_state.implementation_uniform_buffers.size();
		scene_state.implementation_uniform_buffers.resize(p_index + 1);
		for (uint32_t i = from; i < scene_state.implementation_uniform_buffers.size(); i++) {
			scene_state.implementation_uniform_buffers[i] = RD::get_singleton()->uniform_buffer_create(sizeof(SceneState::UBO));
		}
	}
	RD::get_singleton()->buffer_update(scene_state.implementation_uniform_buffers[p_index], 0, sizeof(SceneState::UBO), &scene_state.ubo, RD::BARRIER_MASK_RASTER);
}
void RenderForwardClustered::_update_instance_data_buffer(RenderListType p_render_list) {