Hello Derak,
The fact that downgrading to Edge 141.0.3537.99-1 immediately fixes the issue strongly points to a regression in Edge 142.x on Linux, likely related to CSP handling or font rendering. This isn’t something you caused, It’s almost certainly a browser-level bug introduced in the latest version. For now, the most reliable workaround is to stay on version 141 until Microsoft releases a fix.
You can also report the bug through Edge Feedback with details like your OS (Ubuntu 24.04.3), Edge version, CSP font errors, and a screenshot.
If you installed via Snap, consider switching to the .deb package from Microsoft Edge for Linux, as Snap confinement sometimes causes font and CSP issues. Additionally, you could experiment with disabling certain flags in edge://flags—especially those related to CSP or strict origin isolation—but this is hit or miss.