Thanks for your screen shots.
I observed the issue as you mentioned. I found and confirmed (via your screen shots), some chart data labels are wrong in the output HTML file. I used the following sample code with your template file:
String filePath = “f:\files\XY.xlsx”;
Workbook workbook = new Workbook(filePath);
workbook.save(filePath + “.out1.htm”, SaveFormat.HTML);
I have logged a ticket with an id “CELLSJAVA-41368” for your issue. We will look into it soon.
Once we have any update on it, we will let you know here.