Can you share a sample file so we can take a closer look?

Sure, below is the source.
Thanks for your comment.

////// 1. A Client request get an excel file

////// 2. Server send response with Java file
// Java file has a process logic like below

    FileInputStream fileFis = new FileInputStream(file);
    XSSFWorkbook fileWb = new XSSFWorkbook(fileFis);
    XSSFSheet fileSh = fileWb.getSheetAt(0);

    // Create Row and Cell, Then Set a Value
    // 5, 2, 4 is just random number for test
    Row fileRow = fileSh.createRow(5);
    Cell fileCell = fileRow.createCell(2, 4);
    fileCell.setCellValue("TEST VALUE");

    fileFis.close();

    // Write the output to a file
    File resultFile = new File("1.xlsx");
    FileOutputStream resultFos = new FileOutputStream(resultFile);
    fileWb.write(resultFos);
    resultFos.close();

    return resultFile;

////// 3. Client get a response from the server and SheetJS works like below

    req.onload = function(evt) {
        var tags = "No Data";
        var data = new Uint8Array(req.response);

        if (data.length > 0) {
            var workbook = XLSX.read(data, {type:"array"});
            var sheetName = workbook.SheetNames[0];
            tags = XLSX.utils.sheet_to_html(workbook.Sheets[sheetName], { header: '' });
        }

        jQuery("#divBodyFileViewer").html(tags);
    }

I would be pleased if I could attach my sample files.
I found a demo page you made ---- https://oss.sheetjs.com/
The problem I mentioned is occurring there as well when I drop the sample files.

Since, I cannot attach the files, I attach images that I tested on your demo page.

======= CASE:: Cannot Read the Cells I Added =======

======= CASE:: Can Read the Cells I Added After Open the File with Excel Program and save with doing nothing =======

You should be able to add a file here on github, just click and drag the file into the reply window. If you can't, please email it to hello@sheetjs.com.

In any case, If I had to guess it's a POI issue not updating the worksheet range

Wow, I did not know that. What a fool.

The attacked file 1_NoIden.xlsx is the one from POI.
Drag it into the demo page. And then open with excel program. Then save it doing anything.
Re-drag it into the demo page. And then you can see the difference.

1_NoIden.xlsx

It's not obvious that you can drag-drop files. It's written below the box, but there really should have been an upload link or something above the input box.

That said, this is a mixed issue. To explain, go to https://oss.sheetjs.com/cfb-editor/#/ and drag-drop the file. Then click xl/worksheets/sheet1.xml and click (View as Text). You will see

That is saying the file range is B1:D9, which is what SheetJS use to determine the sheet range. If you scroll further you'll see references to E8/F8, which are both outside the reported range.

If you have patience, we can open a discussion with the POI project and see if you have to do something different to get the library to update the worksheet range.

As for the other side, the reason we've tried to trust the dimension record is based on the actual worksheet representation. Generating millions of small strings is a massive performance killer in V8 / chrome :(

@Yocoms we raised POI bug 64536.