### 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_NULL(render_buffers);
	if (!render_buffers->has_texture(RB_SCOPE_FORWARD_CLUSTERED, RB_TEX_ROUGHNESS)) {
		RD::DataFormat format = RD::DATA_FORMAT_R8G8B8A8_UNORM;
		uint32_t usage_bits = RD::TEXTURE_USAGE_SAMPLING_BIT | RD::TEXTURE_USAGE_STORAGE_BIT;
		if (render_buffers->get_msaa_3d() != RS::VIEWPORT_MSAA_DISABLED) {
			usage_bits |= RD::TEXTURE_USAGE_CAN_COPY_TO_BIT;
		} else {
			usage_bits |= RD::TEXTURE_USAGE_COLOR_ATTACHMENT_BIT;
		}
		render_buffers->create_texture(RB_SCOPE_FORWARD_CLUSTERED, RB_TEX_ROUGHNESS, format, usage_bits);
		if (render_buffers->get_msaa_3d() != RS::VIEWPORT_MSAA_DISABLED) {
			usage_bits = RD::TEXTURE_USAGE_COLOR_ATTACHMENT_BIT | RD::TEXTURE_USAGE_CAN_COPY_FROM_BIT | RD::TEXTURE_USAGE_SAMPLING_BIT;
			render_buffers->create_texture(RB_SCOPE_FORWARD_CLUSTERED, RB_TEX_ROUGHNESS_MSAA, format, usage_bits, texture_samples);
		}
	}
}
void RenderForwardClustered::RenderBufferDataForwardClustered::ensure_voxelgi() {