@MorningSleeper Welcome to Bitwarden!
I believe you are not alone when autofill doesn’t work on login.live.com. Autofill on page load doesn’t work and has never worked for me either on that particular site. However, I’m not sure what’s the reason, and if it’s possible to fix it @tgreer .
Also, you can vote for any features you want, such as Overlay popup interface, which, in my opinion, would make “manual” autofill easier to use. Hope that helps!