As identified by benteo in MDLQA-12125:

Steps to reproduce:

1. Either create a quiz with 3 or more questions or use the Demo quiz on the QA testing site.
2. Preview the quiz via the gear menu.
3. Print the page (as pdf to save paper)

Expected result: All quiz questions are shown.

Actual result: Only some questions are shown with blank pages.

Note that this bug only affects a site using the Boost theme. I was able to reproduce the issue on the QA testing site using Firefox 60.0 (64-bit) on Linux.