1Password for Safari isn't working reliably on macOS Sonoma

I received this reply from the 1P support department:

Thanks for testing those for us. I've just checked with our development team and learned that a recent change in Safari now limits a feature 1Password previously used to enable functionality like filtering the inline form autofill menu. We've raised this concern with Apple, and our team is looking into other ways we may be able to resolve this. I don't currently have any indications of if or when this may be resolved, so for the time being, your best option will be to rely on the 1Password icon in the Safari toolbar when visiting a site with many logins that need to be filtered, or you can consider using a different web browser.

This made sense to me when I originally received it as I would expect Apple to make changes that protect privacy and such. However, my coworker is having no such problems using 1Password 7 and version 7.9.11 of the Safari extension. This would mean that the feature is possible, but version 8 and its associated extension is either doing something wrong or has explicitly chosen to implement the feature using tools that don't work as well. Without an explanation of why the new approach is more desirable or offers some other benefit I hope they might reconsider and just make the feature work.