Characters in Unicode Private Use Area fail to render

[Jap2-0]

Attach (recommended) or Link to PDF file here: https://drive.google.com/drive/folders/1UDhozC8FN0-8EfWT0zt8i0ekl85IKPyP
Initially found previewing PDFs at https://www.humblebundle.com/books/tech-book-bundle-get-more-pi-diy-electronics-w-arduino-raspberry-pi-books

Configuration:

• Web browser and its version: Firefox Nightly 106
• Operating system and its version: Windows 10 21H1
• PDF.js version: 2.16.71
• Is a browser extension: No

Steps to reproduce the problem:

1. Open attached PDFs
2. Text is rendered incorrectly (see below)

What is the expected behavior? (add screenshot)

What went wrong? (add screenshot)

Looking further, these characters all appear to come from the Unicode Private Use Area. However, the (invisible) text layer (for copy/past etc.) understands these characters.

[Snuffleupagus]

Duplicate of #15289

[Snuffleupagus]

Please note #15289 (comment) in particular.

[Jap2-0]

Yup, thanks. Poor searching on my part, sorry.