If you use the MetaMask extension, you probably need to change a MetaMask setting to resolve recent issues with incomplete/broken pages: https://github.com/MetaMask/metamask-extension/issues/31094 ''If you do not use that extension:'' The main differences between regular and private windows are: (1) Private windows do not used previously cached files or previously set cookies -- these are stored temporarily in memory for private windows (2) Private windows may have a smaller set of add-ons running because extensions need specific approval to run in private windows For #1, you can clear those yourself: (1) Clear Firefox's Cache See: [[How to clear the Firefox cache]] (only select "Temporary cached files and pages", don't clear other kinds of data) If you have a large hard drive, this might take a few minutes. (2) Remove the site's cookies (save any pending work first). While viewing a page on the site, click the lock icon at the left end of the address bar. After a moment, a "Clear Cookies and Site Data" button should appear at the bottom. Go ahead and click that. Firefox will ask you to confirm; go ahead and confirm. Then try reloading the page. Does that help? For #2, can you spot a difference between the extensions running in regular and private windows (by checking toolbar buttons or the Extensions button drop-down list)?

The MetaMask extension authors have a version 12.12.1 update as you can see at https://addons.mozilla.org/firefox/addon/ether-metamask/versions/