Symfony collection don’t save array but class name

I’ve got symfony form with CollectionType. It’s a multistep form and when im dumping data after each step it saves properly:

AppEntityRezylientnaArchitektura {#654 ▼
  -id: null
  -BezpInf: DoctrineCommonCollectionsArrayCollection {#655 ▼
    -elements: array:1 [▼
      0 => array:3 [▼
        "BezpInf_1" => "0"
        "BezpInf_2" => "1"
        "BezpInf_3" => "1"
      ]
    ]
  }
  -useruuid: "ea9ae76e-b688-11ed-be51-494b48375171"

Form:

$builder->add('useruuid', HiddenType::class, [
                    'data' => $this->getUserUUID(),
                ]);

                $builder->add('BezpInf', CollectionType::class, [
                    'entry_type' => AnswersTempType::class,
                    'allow_extra_fields' => true,
                    'entry_options' => [
                        'label' => false,                   
                    ],
                    'label' => false,
                    // 'by_reference' => false, 
                ]);

Entity:

#[ORMEntity(repositoryClass: RezylientnaArchitekturaRepository::class)]
class RezylientnaArchitektura
{
    #[ORMId]
    #[ORMGeneratedValue]
    #[ORMColumn]
    private ?int $id = null;

    #[ORMColumn(length: 255)]
    private $BezpInf = null;

    #[ORMColumn(length: 255)]
    private ?string $useruuid = null;

    public function __construct()
    {
        $this->BezpInf = new ArrayCollection();
    }

    public function getId(): ?int
    {
        return $this->id;
    }

    public function getBezpInf(): Collection
    {
        return $this->BezpInf;
    }

    public function setBezpInf(string $BezpInf): self
    {
        $this->BezpInf = $BezpInf;

        return $this;
    }

    public function getUseruuid(): ?string
    {
        return $this->useruuid;
    }

    public function setUseruuid(string $useruuid): self
    {
        $this->useruuid = $useruuid;

        return $this;
    }
}

And now tricky part. When i want to save it into db in classic way:

// ...

$em = $this->doctrine->getManager();
$em->persist($answer);
$em->flush();

// ...

it saves like:

When i add to a form

'by_reference' => false

it render in a dump – DoctrineCommonCollectionsArrayCollection@000000000000032f0000000000000000 and save the same.

How can i persist my arraycollection into db properly?