Error "Unexpected instance annotation name" while trying to update plannerExternalReference

Hi! I am trying to update the plannerExternalReferences of a set of planners that I have access to but I am struggling with this error when I call the requests.patch: "The request is invalid:\r\nAn unexpected instance annotation name xxxxxxx was found when reading from the JSON reader, In OData, Instance annotation name must start with @.","innerError".

Here is the function that I am using:

Thanks in advance for any help!

def update_planner_task_references_I(access_token, task_id, current_references, new_url, new_description, etag):
    headers = {
        "Authorization": f"Bearer {access_token}",
        "Content-Type": "application/json",
        "If-Match": etag
    }

    updated_references = {}

    existing_ref_found = False

    for ref_key, details in current_references.items():
        cleaned_details = {
            "@odata.type": details.get("@odata.type", "#microsoft.graph.plannerExternalReference"),
            "alias": details.get("alias"),
            "type": details.get("type", "Other"),
            "@odata.id": details.get("url") if "url" in details else details.get("@odata.id")
        }

        updated_references[ref_key] = {k: v for k, v in cleaned_details.items() if v is not None}

        if details.get("url") == new_url or details.get("@odata.id") == new_url:
            existing_ref_found = True
            print(f"Anexo existente com URL {new_url} (chave: {ref_key}) será atualizado com a nova descrição.")
            updated_references[ref_key]["alias"] = new_description
            updated_references[ref_key]["type"] = "Other"

    if not existing_ref_found:
        new_ref_key = str(uuid.uuid4())
        updated_references[new_ref_key] = {
            "@odata.type": "#microsoft.graph.plannerExternalReference",
            "@odata.id": new_url,
            "alias": new_description,
            "type": "Other"
        }
        print(f"Novo anexo com URL {new_url} (chave gerada: {new_ref_key}) será adicionado.")

    payload = {
        "references": updated_references
    }


    print(json.dumps(payload, indent=2))

    graph_url = f"https://graph.microsoft.com/v1.0/planner/tasks/{task_id}/details"

    print(f"\nUpdating task attachment. {task_id}...")
    response = requests.patch(graph_url, headers=headers, data=json.dumps(payload))
    response.raise_for_status()

    print("Attachment updated successfully!")
    return response.json()