Questions Media encoder change file name adding extra 0(zero)

Pseudo code

    const fileName = `${chapterMarker.name.replace(/\s/g, '_')}.png`;
    const outputPath = join(outputDir.fsName, fileName);

    const pngPreset = new File(presetPath);
    app.encoder.encodeSequence(sequence, outputPath, pngPreset.fsName, app.encoder.ENCODE_IN_TO_OUT, 0);

 expected result  `MPF_Scene_7_Shot_46_Frame_1255.png`
 received result `MPF_Scene_7_Shot_46_Frame_12550.png`