Relationship with custom query

Hi. I am having some trouble implementing a custom query for a relationship. Simplified, there are two models: Item and Location. Each Item BelongsTo a Location, however a Location can be stored in multiple languages and I'd like to fetch the Location in the request user's language. There is also a chance that the Location does not exist in the desired language yet, where it will then need to be fetched from Google Places first.

I have read in another discussion that it should be possible to replace the relationship query completely, but I am not having so much luck with this.

Some code to show what I am trying:

app/Models/Item.php:

class Item extends Model
{
  // ...

  public static function boot()
  {
    parent::boot();
    self::retrieved(function ($item) {
      Log::debug('Item::boot()', ['location' => $item->location]);
      if ($item->location === null) {
        $item->location = Location::fetchFromGooglePlaces(
          $item->googlePlaceID,
          App::currentLocale(),
        );
      }
      return $item;
    });
  }

  public function location(): BelongsTo
  {
    Log::debug('Item->location', [
      'googlePlaceID' => $this->googlePlaceID,
      'id' => $this->id,
      'language' => App::currentLocale(),
    ]);
    $relation = $this->belongsTo(Location::class);
    $relation->setQuery(
      Location::where([
        'googlePlaceID' => $this->googlePlaceID,
        'language' => App::currentLocale(),
      ])->getQuery(),
    );
    return $relation;
  }
}

app/Http/Controllers/ItemController.php:

class ItemController extends Controller
{
  public function search(ItemSearchRequest $request)
  {
    $validated = $request->safe(['query']);
    $searchQuery = $validated['query'] ?? null;

    $itemsQuery = Item::where('is_given', false);

    if ($searchQuery !== null) {
      $itemsQuery->where(function (Builder $builder) use ($searchQuery) {
        $builder
          ->whereFullText('name', $searchQuery)
          ->orWhereFullText('description', $searchQuery);
      });
    }

    $items = $itemsQuery->paginate(12);

    foreach ($items as $itemDebug) {
      Log::debug('ItemController->search', ['location' => $itemDebug->location]);
    }

    return view('pages.search', [
      'items' => $items,
    ]);
  }
}

The log output from the above is:

local.DEBUG: Item->location {"googlePlaceID":"ChIJawqVBkRfzB0RDN1rJqRkMGQ","id":1,"language":"en"} 
local.DEBUG: Item::boot() {"location":{"App\\Models\\Location":{"id":7,"name":"Parklands","language":"en","googlePlaceID":"ChIJawqVBkRfzB0RDN1rJqRkMGQ"}}} 
local.DEBUG: Item->location {"googlePlaceID":null,"id":null,"language":"en"} 
local.DEBUG: ItemController->search {"items":1} 
local.DEBUG: ItemController->search {"location":null} 

The strange part about this (in my opinion) is that Item->location() is called twice. Once with an id and once without. The without variant always happens after the with variant, and overwrites the location to null.

I can fix this by adding a check for the id around the custom query:

public function location(): BelongsTo
{
  Log::debug('Item->location', [
    'googlePlaceID' => $this->googlePlaceID,
    'id' => $this->id,
    'language' => App::currentLocale(),
  ]);
  $relation = $this->belongsTo(Location::class);
  if ($this->id) {
    $relation->setQuery(
      Location::where([
        'googlePlaceID' => $this->googlePlaceID,
        'language' => App::currentLocale(),
      ])->getQuery(),
    );
  }
  return $relation;
}

But why is this happening, or necessary? I feel like I am treating a symptom, and not a cause.