Here are a few troubleshooting steps you can try to resolve this issue:

1. Check Odoo PDF Viewer Settings: Ensure that the PDF viewer within Odoo is configured correctly. Sometimes, updating or resetting the viewer settings can resolve such issues.

2. Browser Compatibility: If you are experiencing this issue in a specific browser, try opening Odoo in another browser or incognito mode to check if the issue persists. Sometimes, browser extensions or settings can interfere with file rendering.

3. Clear Cache and Cookies: Clear your browser cache and cookies to ensure no outdated settings or files are interfering with PDF display.

4. Check for Module Conflicts: If you have installed third-party modules, disable them one by one to see if one of them is causing the conflict.

I'm experiencing the same problem and I've reached out to support about it. The AI is still functioning, but to confirm its accuracy, you'll need to download the file, which adds a bit of extra effort ;)

When I looked yesterday no one had this issue.  So I posted that I am having this exact same issue and now see this post.  Maddening.