### 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
ERR_FAIL_COND(p_render_buffers.is_null());
	if (p_render_buffers->has_texture(RB_SCOPE_SSIL, RB_LAST_FRAME)) {
		Size2i size = p_render_buffers->get_internal_size();
		uint32_t mipmaps = p_render_buffers->get_texture_format(RB_SCOPE_SSIL, RB_LAST_FRAME).mipmaps;
		for (uint32_t v = 0; v < p_render_buffers->get_view_count(); v++) {
			RID source = p_render_buffers->get_internal_texture(v);
			RID dest = p_render_buffers->get_texture_slice(RB_SCOPE_SSIL, RB_LAST_FRAME, v, 0);
			copy_effects->copy_to_rect(source, dest, Rect2i(0, 0, size.x, size.y));
			int width = size.x;
			int height = size.y;
			for (uint32_t m = 1; m < mipmaps; m++) {
				width = MAX(1, width >> 1);
				height = MAX(1, height >> 1);
				source = dest;
				dest = p_render_buffers->get_texture_slice(RB_SCOPE_SSIL, RB_LAST_FRAME, v, m);
				copy_effects->make_mipmap(source, dest, Size2i(width, height));
			}
		}
	}
}
void RenderForwardClustered::_pre_opaque_render(RenderDataRD *p_render_data, bool p_use_ssao, bool p_use_ssil, bool p_use_gi, const RID *p_normal_roughness_slices, RID p_voxel_gi_buffer) {