QSslSocket::PeerVerifyMode::VerifyNone is ignored on iOS

In the startup code of my application, I'm disabling ssl verification globally by doing this:

    auto ssl = QSslConfiguration::defaultConfiguration();
    ssl.setPeerVerifyMode(QSslSocket::PeerVerifyMode::VerifyNone);
    QSslConfiguration::setDefaultConfiguration(ssl);

Later in the code I'm setting up a QML Image item pointing to an https-source with a self-signed certificate, roughly like this:

Image {
  source: "https://example.com/my/image.jpg"
}

On all other platforms (tested on macOS, Linux, Windows, Android) this works fine, but on iOS loading fails and the following error message is logged:

QML Image: SSL handshake failed