Dúvida em buscar alunos

Olá, pessoal!

Estou com dificuldade para entender o erro que surgiu ao buscar os alunos. O meu arquivo buscar-alunos.php está assim:

use Alura\Doctrine\Entity\Aluno;
    use Alura\Doctrine\Entity\Telefone;
    use Alura\Doctrine\Helper\EntityManagerFactory;

    require_once __DIR__ . '/../vendor/autoload.php';


    $entityManagerFactory = new EntityManagerFactory();
    $entityManager = $entityManagerFactory->getEntityManager();

    $alunoRepository = $entityManager->getRepository(Aluno::class);

    /** @var Aluno[] $alunoList     */
    $alunoList = $alunoRepository->findAll();

    foreach ($alunoList as $aluno) :
        $telefones = $aluno
        ->getTelefones()
        ->map(function (Telefone $telefone) {
            return $telefone->getNumero();
        })
        ->toArray();

        echo "ID: {$aluno->getId()}\n";
        echo "Nome: {$aluno->getNome()}\n";
        echo "Telefones: " . implode(', ', $telefones);

        echo "\n\n";
    endforeach;

E o erro exibido no prompt de comando é:

C:\Edesign\alura\php\doctrine\doctrine-alura>php commands\buscar-alunos.php
PHP Notice:  Undefined index: Aluno in C:\Edesign\alura\php\doctrine\doctrine-alura\vendor\doctrine\orm\lib\Doctrine\ORM\Persisters\Entity\BasicEntityPersister.php on line 1779

Notice: Undefined index: Aluno in C:\Edesign\alura\php\doctrine\doctrine-alura\vendor\doctrine\orm\lib\Doctrine\ORM\Persisters\Entity\BasicEntityPersister.php on line 1779
PHP Notice:  Trying to access array offset on value of type null in C:\Edesign\alura\php\doctrine\doctrine-alura\vendor\doctrine\orm\lib\Doctrine\ORM\Persisters\Entity\BasicEntityPersister.php on line 1783

Notice: Trying to access array offset on value of type null in C:\Edesign\alura\php\doctrine\doctrine-alura\vendor\doctrine\orm\lib\Doctrine\ORM\Persisters\Entity\BasicEntityPersister.php on line 1783
PHP Warning:  Invalid argument supplied for foreach() in C:\Edesign\alura\php\doctrine\doctrine-alura\vendor\doctrine\orm\lib\Doctrine\ORM\Persisters\Entity\BasicEntityPersister.php on line 1783

Warning: Invalid argument supplied for foreach() in C:\Edesign\alura\php\doctrine\doctrine-alura\vendor\doctrine\orm\lib\Doctrine\ORM\Persisters\Entity\BasicEntityPersister.php on line 1783
PHP Notice:  Undefined index: Aluno in C:\Edesign\alura\php\doctrine\doctrine-alura\vendor\doctrine\orm\lib\Doctrine\ORM\PersistentCollection.php on line 168

Notice: Undefined index: Aluno in C:\Edesign\alura\php\doctrine\doctrine-alura\vendor\doctrine\orm\lib\Doctrine\ORM\PersistentCollection.php on line 168
PHP Fatal error:  Uncaught Error: Call to a member function setValue() on null in C:\Edesign\alura\php\doctrine\doctrine-alura\vendor\doctrine\orm\lib\Doctrine\ORM\PersistentCollection.php:168
Stack trace:
#0 C:\Edesign\alura\php\doctrine\doctrine-alura\vendor\doctrine\orm\lib\Doctrine\ORM\Internal\Hydration\ObjectHydrator.php(511): Doctrine\ORM\PersistentCollection->hydrateAdd(Object(Alura\Doctrine\Entity\Telefone))
#1 C:\Edesign\alura\php\doctrine\doctrine-alura\vendor\doctrine\orm\lib\Doctrine\ORM\Internal\Hydration\ObjectHydrator.php(162): Doctrine\ORM\Internal\Hydration\ObjectHydrator->hydrateRowData(Array, Array)
#2 C:\Edesign\alura\php\doctrine\doctrine-alura\vendor\doctrine\orm\lib\Doctrine\ORM\Internal\Hydration\AbstractHydrator.php(153): Doctrine\ORM\Internal\Hydration\ObjectHydrator->hydrateAllData()
#3 C:\Edesign\alura\php\doctrine\doctrine-alura\vendor\doctrine\orm\lib\Doctrine\ORM\Persisters\Entity\BasicEntityPersister.php(952): Doctrine\ORM\Internal\Hydration\AbstractHydrator->hydrateAll(Object(Doctrine\DBAL\Dri in C:\Edesign\alura\php\doctrine\doctrine-alura\vendor\doctrine\orm\lib\Doctrine\ORM\PersistentCollection.php on line 168

Fatal error: Uncaught Error: Call to a member function setValue() on null in C:\Edesign\alura\php\doctrine\doctrine-alura\vendor\doctrine\orm\lib\Doctrine\ORM\PersistentCollection.php:168
Stack trace:
#0 C:\Edesign\alura\php\doctrine\doctrine-alura\vendor\doctrine\orm\lib\Doctrine\ORM\Internal\Hydration\ObjectHydrator.php(511): Doctrine\ORM\PersistentCollection->hydrateAdd(Object(Alura\Doctrine\Entity\Telefone))
#1 C:\Edesign\alura\php\doctrine\doctrine-alura\vendor\doctrine\orm\lib\Doctrine\ORM\Internal\Hydration\ObjectHydrator.php(162): Doctrine\ORM\Internal\Hydration\ObjectHydrator->hydrateRowData(Array, Array)
#2 C:\Edesign\alura\php\doctrine\doctrine-alura\vendor\doctrine\orm\lib\Doctrine\ORM\Internal\Hydration\AbstractHydrator.php(153): Doctrine\ORM\Internal\Hydration\ObjectHydrator->hydrateAllData()
#3 C:\Edesign\alura\php\doctrine\doctrine-alura\vendor\doctrine\orm\lib\Doctrine\ORM\Persisters\Entity\BasicEntityPersister.php(952): Doctrine\ORM\Internal\Hydration\AbstractHydrator->hydrateAll(Object(Doctrine\DBAL\Dri in C:\Edesign\alura\php\doctrine\doctrine-alura\vendor\doctrine\orm\lib\Doctrine\ORM\PersistentCollection.php on line 168

Alguém pode me dar um help?

Desde já, agradeço.