Using Document Generator, Chinese characters are not supported when exporting in PDF

Using Document Generator, Chinese characters are not supported when exporting in PDF. It generates rectangles instead of said characters.

Steps to reproduce:

1. Add Chinese characters to, for instance, the issue description or summary.
2. Export using a template that contains the description or summary.

Actual result:

• Characters appear as squares:

Expected result:

• Characters should appear correctly, like in the example below: