What happens files from this site? https://www.irs.gov/downloads/irs-pdf

What OS? What Desktop? X11 or Wayland?

Same thing.

Linux Mint 20.3 Cinnamon X11

FWIW, after rebooting it's fine but as soon as a suspend/wake cycle has occured PDFs become transparent without fail.

What happens in KDE?

Try downloading Firefox from Mozilla, run firefox-bin from the folder and see if you have the same issue. https://www.mozilla.org/en-US/firefox/all/#product-desktop-release

As a test, with a different drive, I would try a different OS(wink wink) or try something else on a live usb stick.

Operating System: openSUSE Tumbleweed 20240524 KDE Plasma Version: 6.0.4 KDE Frameworks Version: 6.2.0 Qt Version: 6.7.0 Kernel Version: 6.9.1-1-default (64-bit) Graphics Platform: X11 Processors: 16 × AMD Ryzen 7 5825U with Radeon Graphics Memory: 62.1 GiB of RAM Graphics Processor: AMD Radeon Graphics Manufacturer: HP Product Name: HP ProBook 455 15.6 inch G9 Notebook PC

I have tried with Tumbleweed on a live USB, the problem is that it uses the nouveau driver (I think) rather than the nVIDIA one and as a result I can't put the computer to sleep to see if it also breaks displaying PDFs (it crashes and I have to reset)

Roger that, sounds like you will need to install for a proper test. Did you see if KDE has the same issue? Did you try Firefox in Troubleshoot Mode? https://support.mozilla.org/en-US/kb/diagnose-firefox-issues-using-troubleshoot-mode#search104

Here are the drivers I see for Linux from nvidia for your card. I think their site has the listing backwards, but you can see which is the latest driver.

https://www.nvidia.com/Download/driverResults.aspx/226768/en-us/

New Feature Branch New Feature Branch drivers provide early adopters and bleeding edge developers access to the latest driver features before they are integrated into the Production Branches

Version: 550.90.07 Release Date: 2024.6.4 Operating System: Linux 64-bit Language: English (US) File Size: 293.33 MB

Production Branch Production Branch drivers provide ISV certification and optimal stability and performance for Unix customers. This driver is most commonly deployed at enterprises, providing support for the sustained bug fix and security updates commonly required.

Version: 545.29.02 Release Date: 2023.10.31 Operating System: Linux 64-bit Language: English (US) File Size: 309.74 MB