Keyboard scrolling on PDF pages doesn't work

Description of the issue:

Scrolling using Keyboard in URLs with PDF extension do not work. Can’t use PgUp, PgDn, can’t use up-arrow, down-arrow. I can only scroll using the mouse wheel or scroll bar. On any other web page, like with a HTML extension, the keyboard works as it should.

How can this issue be reproduced?

  1. Go to any URL with a PDF extension. For example, https://www.skybrary.aero/bookshelf/books/262.pdf

  2. Try and use any keyboard key to advance in the PDF.

Expected result:

That I be able to scroll using the keyboard like any other web page.

Brave Version( check About Brave):

1.26.77

Additional Information:

EL CAPITAN. Not upgrading due to aged hardware. If El Capitan is the issue and Brave won’t play nice with it, then you shouldn’t allow it to be installed on El Capitan.
NO EXTENSIONS ENABLED. Nothing could be causing this other than Brave.

@mculver,
On my end, I’m able to navigate/scroll through the PDF you shared without issue on both macOS and Windows systems. It could be due to the version you’re using (El Capitan) but that seems unlikely to me. That said, if you don’t have any extensions installed, I’m wondering if it’s perhaps related to Chromium. Do you have another Chromium browser (Chrome, Opera, Edge, etc) you’d be willing to test the behavior on? Additional (while not Chromium), can you test using Safari and confirm whether or not you get this behavior?