### 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
sdfgi = gi.create_sdfgi(p_environment, p_world_position, requested_history_size);
		rb->set_custom_data(RB_SCOPE_SDFGI, sdfgi);
	} else {
		
		sdfgi->update(p_environment, p_world_position);
	}
}
int RenderForwardClustered::sdfgi_get_pending_region_count(const Ref<RenderSceneBuffers> &p_render_buffers) const {
	Ref<RenderSceneBuffersRD> rb = p_render_buffers;
	ERR_FAIL_COND_V(rb.is_null(), 0);
	if (!rb->has_custom_data(RB_SCOPE_SDFGI)) {
		return 0;
	}
	Ref<RendererRD::GI::SDFGI> sdfgi = rb->get_custom_data(RB_SCOPE_SDFGI);
	int dirty_count = 0;
	for (const RendererRD::GI::SDFGI::Cascade &c : sdfgi->cascades) {
		if (c.dirty_regions == RendererRD::GI::SDFGI::Cascade::DIRTY_ALL) {
			dirty_count++;
		} else {
			for (int j = 0; j < 3; j++) {
				if (c.dirty_regions[j] != 0) {
					dirty_count++;
				}
			}
		}
	}
	return dirty_count;
}
AABB RenderForwardClustered::sdfgi_get_pending_region_bounds(const Ref<RenderSceneBuffers> &p_render_buffers, int p_region) const {