For an unknown reason, Firefox Browser doesn't render portions of text on some pages, leaving invisible areas. I'm using the latest version (95.0.2) on Windows 10, but this was a problem in other recent versions. It only happens on some systems. No other browser I've tried has the same problem, so the issue is definitely Firefox-specific. One example of a problematic page is [https://arxiv.org/ arxiv.org], another one is [https://www.caltech.edu/about/news Caltech News]; see the attached screenshots for how Firefox renders these pages on my system. Here's what I found out. # The issue goes away if I disable the "Allow pages to choose their own fonts, instead of your selections above" font setting. # The issue remains even if I disable/uninstall all add-ons. # Refresh-install doesn't resolve the issue. # After uninstalling and installing Firefox cleanly again, with old settings auto-imported (bookmarks, history, logins ...) and no add-ons present, the issue is not present at first. However, if I enable "Open previous windows and tabs" option to restore my session on startup, the issue reappears after I close and re-open Firefox a couple of times, and doesn't go away after that. It doesn't matter whether the problematic pages are included in the restored session or not; they will simply not show all text as expected if I visit them. # Deleting the entire cache, cookies, site data and site settings doesn't help. # Opening Firefox in ''Troubleshoot mode'' make the problem disappear, but it returns immediately when I leave the ''Troubleshoot mode''. Any ideas how to fix this?