How can a person responsible for a lead be automatically assigned?

Question

Bitrix24

I transfer the lead to B24 of the client something like this:

$result = \App\B24Rest::call(
                        'crm.lead.add',
                        ['FIELDS' => [
                                'TITLE' => 'Сообщение из формы №'.$arElement['ID'],
                                'NAME' => $arElement['NAME'],
                                //'LAST_NAME' => 'Петров',
                                //'EMAIL' => [
                                //        '0' => ['VALUE' => '[email protected]', 'VALUE_TYPE' => 'WORK', ]
                                //    ],
                                'PHONE' => [
                                        '0' => ['VALUE' => $arElement['PREVIEW_TEXT'], 'VALUE_TYPE' => 'WORK', ]
                                    ]
                                ],
                                'UTM_CAMPAIGN' => $arElement['PROPERTY_UTM_CAMPAIGN_VALUE'],
                                'UTM_CONTENT' => $arElement['PROPERTY_UTM_CONTENT_VALUE'],
                                'UTM_MEDIUM' => $arElement['PROPERTY_UTM_MEDIUM_VALUE'],
                                'UTM_SOURCE' => $arElement['PROPERTY_UTM_SOURCE_VALUE'],
                                'UTM_TERM' => $arElement['PROPERTY_UTM_TERM_VALUE'],
                                'ASSIGNED_BY_ID' => 28
                            ]
                                
                    );

But not the user with ID 28 is appointed responsible, but another user (with ID 12)
What can change the responsible in B24? I expected that it could be some kind of business process, but their list is empty.

What settings can still lead to this? Maybe I'm not passing the id correctly? Tried another line both as U28 and as U_28 - no result.

How to localize the problem?