Password managers rarely are able to autofill 100% of the time. Autofill breaking is not a very strong indicator of a phishing attempt, people are used to manually filling the password in sometimes for totally legit sites.

It's far too common for websites to redirect to some separate domain for sign in which isn't the one originally used to sign up, getting users used to "oh gotta copy the password again" as a totally normal thing that happens

As I said in my comment above, sometimes it’s necessary as websites break the auto fill, or mobile apps don’t offer the password manager sheet.

This very story illustrates how people will override their password manager's builtin protections when panic ensues.

If only everyone did everything perfectly all the time, we wouldn't have any issues!