Eloquent query for morphToMany - problem with generated SQL code

I have problem with Eloquent morphToMany

public function categories()
{
    return $this->morphToMany(Category::class, 'categoryable')->withTimestamps();
}

# part of query
return $this->builder->whereHas('categories', function ($query) use ($val) {
    $query->whereIn('categories.id', $val);
});

this part of query produce MySQL code (deleted not required here parts of code):

select
    *
from
    `categories`
INNER join `categoryables` on `categories`.`id` = `categoryables`.`category_id`
where
      `categoryables`.`categoryable_type` = 'App\Models\Volunteering'

Tested in DBeaver and this code returns empty results, when I look to database table then should be any results. Comment out WHERE clause and records are showed. So, I copy and paste "App\Models\Volunteering" to query, no, it's correct. Try use LIKE with % and without, no records. But when I test with

WHERE `categoryables`.`categoryable_type` LIKE 'App%'

query shows results. But this query is generated by Eloquent. What is wrong?

Tested on MySQL 5.7 and MariaDB 10.2, same problem.