DOCX to PDF works after saving file only [JAVA]

Question

The code provided bellow kinda works, the problemn i'm trying to solve is that i'm already able to save my docx localy. When im trying to covert it to pdf, i get blank pages or pages with only the docx header. But when i open the file manualy with Libre office or free office and save it without doing any alteration, and run the conversion again, the file converts perfectly just how i needed it. Anyone know why this happens and how could i replicate that behavior without having to actually opeing and saving the file, since i need to do all this processes programaticaly?

Im trying to covert a DOCX to PDF using:

<dependency>      
    <groupId>fr.opensagres.xdocreport</groupId>           
    <artifactId>org.apache.poi.xwpf.converter.pdf</artifactId>
    <version>1.0.6</version>  
</dependency>

So far my code is:

public byte[] converterXmlToDocx(Long idModeloDocumento) throws Docx4JException {
    try {
        byte[] gzipXml = buscarModeloDocumento(idModeloDocumento);
        byte[] xmlData = descompactarGzip(gzipXml);

        WordprocessingMLPackage pkg = WordprocessingMLPackage.load(new    ByteArrayInputStream(xmlData));

        ByteArrayOutputStream outputStream = new ByteArrayOutputStream();
        pkg.save(outputStream);

        //saves file localy
        String outputFilePath = "src/main/resources/test1.docx";
        File outputDocxFile = new File(outputFilePath);
        pkg.save(outputDocxFile);

        return outputStream.toByteArray();
    } catch (Docx4JException | IOException e) {
        e.printStackTrace();
        throw new Docx4JException("Erro converting xml to docx", e);
    }
}


public void convertLOCAL(String docxFilePath, String pdfFilePath) {
    try {
        FileInputStream docxFile = new FileInputStream(docxFilePath);
        XWPFDocument document = new XWPFDocument(docxFile);

        FileOutputStream pdfFile = new FileOutputStream(pdfFilePath);
        PdfOptions options = PdfOptions.create();
        PdfConverter.getInstance().convert(document, pdfFile, options);

        docxFile.close();
        pdfFile.close();

        System.out.println("Sucess");
    } catch (IOException ex) {
        System.out.println(ex.getMessage());
        throw new RuntimeException("Conversion Error", ex);
    }
}

What i do above is generating the docx file with the first method them converting it using the second method in my controller, passing input docx path and output pdf path.