### 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
radiance_texture = sky.sky_get_radiance_texture_rd(sky_rid);
			} else {
				
				draw_sky = false;
			}
			if (draw_sky || draw_sky_fog_only) {
				
				sky.update_res_buffers(rb, p_render_data->environment, time, sky_energy_multiplier);
			}
			RD::get_singleton()->draw_command_end_label();
		}
	} else {
		clear_color = p_default_bg_color;
	}
	bool debug_voxelgis = get_debug_draw_mode() == RS::VIEWPORT_DEBUG_DRAW_VOXEL_GI_ALBEDO || get_debug_draw_mode() == RS::VIEWPORT_DEBUG_DRAW_VOXEL_GI_LIGHTING || get_debug_draw_mode() == RS::VIEWPORT_DEBUG_DRAW_VOXEL_GI_EMISSION;
	bool debug_sdfgi_probes = get_debug_draw_mode() == RS::VIEWPORT_DEBUG_DRAW_SDFGI_PROBES;
	bool depth_pre_pass = bool(GLOBAL_GET("rendering/driver/depth_prepass/enable")) && depth_framebuffer.is_valid();
	bool using_ssao = depth_pre_pass && !is_reflection_probe && p_render_data->environment.is_valid() && environment_get_ssao_enabled(p_render_data->environment);
	bool continue_depth = false;
	if (depth_pre_pass) { 
		bool needs_pre_resolve = _needs_post_prepass_render(p_render_data, using_sdfgi || using_voxelgi);
		if (needs_pre_resolve) {
			RENDER_TIMESTAMP("GI + Render Depth Pre-Pass (Parallel)");
		} else {
			RENDER_TIMESTAMP("Render Depth Pre-Pass");
		}
		if (needs_pre_resolve) {
			
			RD::get_singleton()->draw_list_begin(depth_framebuffer, RD::INITIAL_ACTION_CLEAR, RD::FINAL_ACTION_CONTINUE, RD::INITIAL_ACTION_CLEAR, RD::FINAL_ACTION_CONTINUE, depth_pass_clear);
			RD::get_singleton()->draw_list_end();