Thanks for the template file and stack trace.
After an initial test, I observed the issue as you mentioned by using the following sample code with your template file. I found an exception “java.lang.NumberFormatException” when loading the HTML file:
Workbook workbook = new Workbook("InputFile.html", new HTMLLoadOptions(LoadFormat.HTML));
I have logged a ticket with an id “CELLSJAVA-42434” for your issue. We will look into it soon.
Once we have an update on it, we will let you know here.