Laravel 5.4 Hybrid Relationships not working

[Vasiliy-Bondarenko]

use Jenssegers\Mongodb\Eloquent\Model;

class Post extends Model
{
    protected $connection = 'mongodb';
    protected $table = 'scheduled_posts';

    public function account()
    {
        return $this->belongsTo(Account::class, 'acc_id', 'id'); // Account model is in MySQL!!
    }
}

in Controller

        $p = Post::first();
        $a = $p->account;

Resulting error:

Call to a member function compileSelect() on null
in vendor/laravel/framework/src/Illuminate/Database/Query/Builder.php:1650

screen: http://joxi.ru/L21LYKWF8VY8am

before upgrading to Laravel 5.4 was working fine...

[n1ks2n]

Met the same issue after updating from 5.2 to 5.4