QModbusClient::processResponse() is never called

class MyServer : public QModbusTcpServer
{
    Q_OBJECT

public:
    MyServer(QObject* parent = nullptr) : QModbusTcpServer(parent) {}

protected:
    QModbusResponse processRequest(const QModbusPdu &request) override
    {
        qDebug() << "Processing request:" << request;
        auto result = QModbusTcpServer::processRequest(request);
        qDebug() << "\tResult:" << result;
        return result;
    }
    QModbusResponse processPrivateRequest(const QModbusPdu &request) override
    {
        qDebug() << "Processing private request:" << request;
        auto result = QModbusTcpServer::processPrivateRequest(request);
        qDebug() << "\tResult:" << result;
        return result;
    }
};

class MyClient : public QModbusTcpClient
{
    Q_OBJECT

public:
    MyClient(QObject* parent = nullptr) : QModbusTcpClient(parent) {}

protected:
    bool processPrivateResponse(const QModbusResponse &response, QModbusDataUnit *data) override
    {
        qDebug() << "Processing private response:" << response << data;
        bool result = QModbusTcpClient::processPrivateResponse(response, data);
        qDebug() << "\tResult:" << result;
        return result;
    }

    bool processResponse(const QModbusResponse &response, QModbusDataUnit *data) override
    {
        qDebug() << "Processing response:" << response << data;
        bool result = QModbusTcpClient::processResponse(response, data);
        qDebug() << "\tResult:" << result;
        return result;
    }
};