### 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
}
#ifdef REAL_T_IS_DOUBLE
		{
			defines += "\n#define USE_DOUBLE_PRECISION \n";
		}
#endif
		scene_shader.init(defines);
	}
	
	{
		RD::SamplerState sampler;
		sampler.mag_filter = RD::SAMPLER_FILTER_NEAREST;
		sampler.min_filter = RD::SAMPLER_FILTER_NEAREST;
		sampler.enable_compare = true;
		sampler.compare_op = RD::COMPARE_OP_LESS;
		shadow_sampler = RD::get_singleton()->sampler_create(sampler);
	}
	render_list_thread_threshold = GLOBAL_GET("rendering/limits/forward_renderer/threaded_render_minimum_instances");
	_update_shader_quality_settings();
	resolve_effects = memnew(RendererRD::Resolve());
	taa = memnew(RendererRD::TAA);
	ss_effects = memnew(RendererRD::SSEffects);
}
RenderForwardClustered::~RenderForwardClustered() {
	if (ss_effects != nullptr) {
		memdelete(ss_effects);
		ss_effects = nullptr;
	}
	if (taa != nullptr) {
		memdelete(taa);