I solved it with:
1. add function getLanguageId to CategoryDataProvider class /src/Adapter/Category/CategoryDataProvider.php
public function getLanguageId()
{
return $this->languageId;
}
2. edit switch default: in function buildView in /src/PrestaShopBundle/Form/Admin/Type/TypeaheadProductCollectionType.php
change:
default:
$product = $this->productAdapter->getProduct($id);
$collection[] = [
'id' => $id,
'name' => reset($product->name) . ' (ref:' . $product->reference . ')',
'image' => $product->image,
];
break;
to:
default:
$id_lang=$this->categoryAdapter->getLanguageId();
$product = $this->productAdapter->getProduct($id,false,$id_lang);
$collection[] = [
'id' => $id,
'name' => ($product->name) . ' (ref:' . $product->reference . ')',
'image' => $product->image,
];
break;