laravel whereHas results weird

product model

    public function country() {
        return $this->hasMany('App\Models\ProductCountry', 'product_id', 'id');
    }

the controller

$product = Product::where('mall_' . $this->mall_id, '=', 1)
    ->whereHas('country', function ($i) use ($me) {
        return $i->where('country_id', $me->country_id);
    })
    ->find($key);

the raw SQL:

select * from `product` where `mall_3` = '1' and exists (select * from `product_country` where `product_country`.`product_id` = `product`.`id` and `country_id` = '109') and `product`.`id` = '3' and `product`.`deleted_at` is null limit 1

above SQL return no results(when the product id = 3

below SQL return the correct result(when the product id = 6)

select * from `product` where `mall_3` = '1' and exists (select * from `product_country` where `product_country`.`product_id` = `product`.`id` and `country_id` = '109') and `product`.`id` = '6' and `product`.`deleted_at` is null limit 1

have no idea, the query look like no problem

via Chebli Mohamed