Hi Firefox support, I’m experiencing a persistent issue with Google Fonts (.woff2) on Windows 10. Only on some but not all pages whoch are using Google Font woff2: Fonts display correctly after starting Firefox, but as soon as I reload the pages with for the first time, they appear corrupted and remain broken. Private Browsing mode renders the fonts correctly, and Chrome does not have this problem. Below is a detailed list of everything I’ve tried with ChatGPT so far to troubleshoot the issue. (OS: latest Windows 10) Browser: Firefox (freshly installed, no sync) Behavior: Example site: https://www.linguee.de/ Steps already attempted: Disabled all extensions Tested in Firefox Safe Mode / Troubleshoot Mode Created a new Firefox profile Fresh Firefox installation without signing in Deleted all relevant caches: %LOCALAPPDATA%\Mozilla\Firefox\Profiles\<profile>\cache2 %LOCALAPPDATA%\Mozilla\Firefox\Profiles\<profile>\storage %APPDATA%\Mozilla\Firefox\Profiles\<profile>\startupCache %LOCALAPPDATA%\Mozilla\ Verified / adjusted Firefox config in about:config: browser.display.use_document_fonts = 1 gfx.webrender.all = false WebRender running in WebRender (Software) mode privacy.resistFingerprinting = false browser.cache.disk.enable = false network.http.rcwn.enabled = false accessibility.force_disabled = 1 Disabled hardware acceleration for testing Tested DirectWrite / Direct3D settings Recalibrated ClearType Ran sfc /scannow to repair system fonts Temporarily disabled antivirus / web protection Tested behavior in private mode versus normal mode Observed that hard reload (Ctrl + F5) does not fix fonts Noted that only .woff2 (Google Fonts) are affected; system fonts render normally Summary: Issue is not caused by extensions, profile, cache, or a fresh install Private Browsing works → problem is related to persistent normal-mode caching or rendering Only occurs in normal windows, consistently reproducible after first reload Problem seems specific to .woff2 font handling and Firefox’s rendering pipeline on Windows 10