The relationship is not added at creation

[dorinniscu]

PHP: 7.3
Laravel: 5.8
Laravel Scout: 7.1
Algolia Scout extended: 1.6

class Page extends Model
{   
  use Searchable;

  public function toSearchableArray()
  {
    $array = [
      'title' => optional($this->content)->title,
      'extra' => $this->extra,
    ];

    return $array;
  }

  public function content()
  {
    return $this->morphOne(Content::class, 'contentable');
  }
   
  protected $fillable = ['extra'];

  protected $with = ['content'];
}

class Content extends Model
{
    public function contentable()
    {
      return $this->morphTo();
    }

    protected $fillable = ['title'];
   
    protected $touches = ['contentable'];
}

class PageController extends Controller
{
  public function store(Request $request)
  {
    $page = Page::create($request->all());

    $page->content()->create($request->all());
   
    return $page;
  }

  public function update(Request $request, $id)
  {
    $page = $this->findOrFail($id);

    $page->update($request->all());

    $page->content->update($request->all());

    $page = $page->fresh();

    return $page;
  }
}

Scout import of existing instances works fine, all instances are in sync.

On update the sync works fine, $touches does the job.

$array = [
  'title' => 'Title',
  'extra' => 'Extra field',
];

On store the content relation is null and not updated when is created.

$array = [
  'title' => null,
  'extra' => 'Extra field',
];