ResponsiveVoice.js sometimes speak on Indonesian Female voice when i use Indonesian male voice

Question

Hello i successfully implementing 'Indonesian Male' Text-To-Speech using ResponsiveVoice.js but sometimes it's returning 'Female Voice', why that happen ?

here is my code

var paramSpeak = {
    onstart: onStartSpeak,
    onend: onEndSpeak,
    pitch: 1
}

function setResponse(val) { 
    paramSpeak.onstart(val);
    responsiveVoice.speak(val,"Indonesian Male",paramSpeak);
}