Objecttype v2 mapping: Upload in repeating group "replaces" all other data in repeating group on submit

[LaurensBurger]

Product versie / Product version

2.6.x

Customer reference

DH

Omschrijf het probleem / Describe the bug

When "Bijlage informatieobjecttype" is set and a upload is present in a repeating group it replaces all values in the repeating group with just the result of the attachment upload:

json output with upload:

{
    "type": "https://objecttypen.nl/api/v2/objecttypes/6e3a6f27-d248-46eb-853d-1373a1b9c6b0",
    "record": {
        "typeVersion": 2,
        "data": {
            "step": [
            "https://openzaak.nl/documenten/api/v1/enkelvoudiginformatieobjecten/f9699f02-24fd-4799-8fcf-8c2aac434de0"
            ]
        },
        "startAt": "2024-09-20"
    }
}

output no upload:

{
    "type": "https://objecttypen.nl/api/v2/objecttypes/6e3a6f27-d248-46eb-853d-1373a1b9c6b0",
    "record": {
        "typeVersion": 2,
        "data": {
            "step": [
                {
                    "tekstveld": "1",
                    "1tekstveld": "a",
                    "eMailadres": "[email protected]",
                    "bestandsupload": []
                }
            ]
        },
        "startAt": "2024-09-20"
    }
}