### 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 DEBUG_ENABLED
			}
#endif
			mesh_surface = surf->surface;
		}
		if (!mesh_surface) {
			continue;
		}
		
		if (shader->uses_time) {
			should_request_redraw = true;
		}
		
		SceneShaderForwardClustered::ShaderData::CullVariant cull_variant;
		if (p_pass_mode == PASS_MODE_DEPTH_MATERIAL || p_pass_mode == PASS_MODE_SDF || ((p_pass_mode == PASS_MODE_SHADOW || p_pass_mode == PASS_MODE_SHADOW_DP) && surf->flags & GeometryInstanceSurfaceDataCache::FLAG_USES_DOUBLE_SIDED_SHADOWS)) {
			cull_variant = SceneShaderForwardClustered::ShaderData::CULL_VARIANT_DOUBLE_SIDED;
		} else {
			bool mirror = surf->owner->mirror;
			if (p_params->reverse_cull) {
				mirror = !mirror;
			}
			cull_variant = mirror ? SceneShaderForwardClustered::ShaderData::CULL_VARIANT_REVERSED : SceneShaderForwardClustered::ShaderData::CULL_VARIANT_NORMAL;
		}
		RS::PrimitiveType primitive = surf->primitive;
		RID xforms_uniform_set = surf->owner->transforms_uniform_set;
		SceneShaderForwardClustered::PipelineVersion pipeline_version = SceneShaderForwardClustered::PIPELINE_VERSION_MAX; 
		uint32_t pipeline_color_pass_flags = 0;
		uint32_t pipeline_specialization = 0;
		if constexpr (p_pass_mode == PASS_MODE_COLOR) {
			if (element_info.uses_softshadow) {