Commented Unassigned: Broken XLSX from XLTX template and gradient fill [14888]

I play with EPPlus 3.1.3.3 from NuGet.
I want create XLSX from XLTX template. My code:
```
var templ = new FileInfo(@"C:\aaa.xltx");
var xlsx = new FileInfo(@"C:\bbb.xlsx");
using (var p = new ExcelPackage(xlsx, templ))
{
p.Save();
}
```
In result - bbb.xlsx always broken. Excel says: "In the book contents which could not be read. Try to restore the contents of the book?".

I'm doing something wrong?

If I override the template I take an ordinary, simple XLSX file, the result may be positive.

Gradient fill in the template completely disappears in the resulting file. This is a mistake?

Comments: Hello! I have no solutions for this problem. I do not use XLTX templates and gradients. A pity. :(