### 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
rl->element_info[p_offset + i - j].repeat = j;
				}
			}
			repeats = 1;
			if (p_render_info) {
				p_render_info[RS::VIEWPORT_RENDER_INFO_DRAW_CALLS_IN_FRAME]++;
			}
		}
		RenderElementInfo &element_info = rl->element_info[p_offset + i];
		element_info.lod_index = surface->sort.lod_index;
		element_info.uses_forward_gi = surface->sort.uses_forward_gi;
		element_info.uses_lightmap = surface->sort.uses_lightmap;
		element_info.uses_softshadow = surface->sort.uses_softshadow;
		element_info.uses_projector = surface->sort.uses_projector;
		if (cant_repeat) {
			prev_surface = nullptr;
		} else {
			prev_surface = surface;
		}
	}
	if (repeats > 0) {
		for (uint32_t j = 1; j <= repeats; j++) {
			rl->element_info[p_offset + element_total - j].repeat = j;
		}
	}
	if (p_update_buffer) {
		_update_instance_data_buffer(p_render_list);
	}
}
_FORCE_INLINE_ static uint32_t _indices_to_primitives(RS::PrimitiveType p_primitive, uint32_t p_indices) {