Something wrong with relations

App.js と ProposalParam 用の HydraAdmin リレーションフォームから始め、次に ProposalType の選択時に生成されるネットワークリクエストを調べます。フィールドメタデータをエンティティのリレーションおよび API レスポンスと比較します。ManyToOne フィールドがネストされた配列ではなく ProposalType の IRI を送信すれば、問題は解決です。

PHP: 8.2
Symfony: ^6
Api platform: ^3.2
Admin api platform: ^3.4.4

I created entity ProposalType.php

#[ORM\OneToMany(mappedBy: 'proposalType', targetEntity: ProposalParam::class)]
private Collection $proposalParams;

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

    public function getProposalParams(): Collection
    {
        return $this->proposalParams;
    }

    public function addProposalParam(ProposalParam $proposalParam): static
    {
        if (!$this->proposalParams->contains($proposalParam)) {
            $this->proposalParams->add($proposalParam);
            $proposalParam->setProposalType($this);
        }

        return $this;
    }

    public function removeProposalParam(ProposalParam $proposalParam): static
    {
        if ($this->proposalParams->removeElement($proposalParam)) {
            // set the owning side to null (unless already changed)
            if ($proposalParam->getProposalType() === $this) {
                $proposalParam->setProposalType(null);
            }
        }

        return $this;
    }

And another entity ProposalParam.php

    #[ORM\ManyToOne(inversedBy: 'proposalParams')]
    #[ORM\JoinColumn(nullable: false)]
    private ?ProposalType $proposalType = null;
    
    public function getProposalType(): ?ProposalType
    {
        return $this->proposalType;
    }

    public function setProposalType(?ProposalType $proposalType): static
    {
        $this->proposalType = $proposalType;

        return $this;
    }

This is pretty simple ManyToOne relation. Generated by make:entity. I'm dont modified this.
Wanted that ProposalParam entity has ProposalType entity by relation, it is simple.

I can create ProposalType via api platform with POST request to /api/proposal_types. And it is successfull.
Then i can set this ProposalType in ProposalParam via POST request to /api/proposal_types. And it is successfull.
Records are inside database and set up like needed.

When i go to admin panel and send request to create ProposalParam i can set ProposalType.

But request sends as array

And error occured Nested documents for attribute "proposalType" are not allowed. Use IRIs instead.
And this is expected, we send array, but api wants IRI.

App.js in admin pretty standart, do not modify something

import { HydraAdmin } from "@api-platform/admin";

export default () => (
    <HydraAdmin entrypoint="http://localhost:9191/api" />
);

Main goal is why system generate select where i need to specify array of ProposalTypes, instead of one ProposalType. Can someone help with it?