Via not displaying font of PDF properly

[mkdir-washington-edu]

Describe the bug
A user pointed us to https://via.hypothes.is/https://rinarxiv.lipi.go.id/lipi/preprint/view/187/225. At that link the PDF shows up in Via with boxes instead of individual characters:

If you download the PDF and open it (in Chrome, Firefox, or Adobe Reader) the characters display normally:

This is also the case if you navigate to the PDF outside of Via: https://rinarxiv.lipi.go.id/lipi/preprint/view/187/225.

To Reproduce
Steps to reproduce the behavior:

1. Download PDF at bottom of issue
2. Open
3. Go to https://via.hypothes.is/https://rinarxiv.lipi.go.id/lipi/preprint/view/187/225
4. Compare

Expected behavior
The PDF should display the same in Via as it does in other places.

Additional context
The PDF:
187-Preprint Text-198-1-10-20210522.pdf

Embedded fonts:

[mkdir-washington-edu]

Last time we reviewed this we said we'd test the PDF in the new PDF.js client on their site and, if the fonts rendered correctly there, we'd review this again.

I tested this on the site and the fonts rendered correctly:

Files is here:
187-Preprint Text-198-1-10-20210522 (2).pdf

I'm adding back to "To review"