cognitive-services-speech-sdk: Sample bookmark listener from tts Azure documentation not working

Hi,

In a java application, I try to use bookmarks for evaluating audio offsets in a text-to-speech conversion and even the sample code from the tts documentation is giving false results.

Any idea on what is the problem in my coding or a limitation that applies ?

Here is the code :

    private void test() {
    String speechSubscriptionKey = "38blabla";
    String serviceRegion = "westeurope";
    config = SpeechConfig.fromSubscription(speechSubscriptionKey, serviceRegion);
    assert (config != null);
    config.setSpeechSynthesisOutputFormat(SpeechSynthesisOutputFormat.Audio24Khz96KBitRateMonoMp3);

    String ssml = "<speak version=\"1.0\" xmlns=\"http://www.w3.org/2001/10/synthesis\" xml:lang=\"en-US\">\r\n"
            + "    <voice name=\"en-US-AriaNeural\">\r\n"
            + "        We are selling <bookmark mark='flower_1'/>roses and <bookmark mark='flower_2'/>daisies.\r\n"
            + "    </voice>\r\n" + "</speak>\r\n" + "";
    assert (ssml != null);

    SpeechSynthesizer synth;
    synth = new SpeechSynthesizer(config, null);
    assert (synth != null);
    synth.BookmarkReached.addEventListener((o, e) -> {
        // The unit of e.AudioOffset is tick (1 tick = 100 nanoseconds), divide by
        // 10,000 to convert to milliseconds.

        System.out.println(
                "Bookmark " + e.getText() + " reached. Audio offset: " + e.getAudioOffset() / 10000 + "ms.");
    });

    // creates voice
    SpeechSynthesisResult result = synth.SpeakSsml(ssml);
    assert (result != null);

And here is the result :

Bookmark flower_1 reached. Audio offset: 50ms.
Bookmark flower_2 reached. Audio offset: 50ms.

Which is not the expected result.

My configuration for this test : Windows 10 with java jdk 1.8.0_301.