I'm using google cloud text-to-speech, using srt files as an input, I convert the srt to ssml with timestamps plus I'm trying to adjust the speech rate to match the same time as in the srt file.

I ran into a problem that I have no idea on how to figure out why. I successfully managed to change the audio length to match the original, but the speech rate won't change - at least right now - on the example the only one that changes is the second line that gets slowed down.

Does anyone know why is that happening?

<speak>
    <s><break time="8000ms"/><prosody rate="47.5%">This is the first subtitle.</prosody><break time="1000ms"/></s>
    <s><break time="1000ms"/><prosody rate="34%">Here comes the second line.</prosody><break time="1000ms"/></s>
    <s><break time="1000ms"/><prosody rate="39.5%">Now the third segment appears.</prosody><break time="1000ms"/></s>
    <s><break time="1000ms"/><prosody rate="35.5%">And this is the fourth one.</prosody><break time="1000ms"/></s>
</speak>