For example https://www.twilio.com/login - here email is entered in one screen, password on next one. But email is not filled automatically despite I have saved email/password. MX5 can fill it.
https://app.mouseflow.com/sign-in - same thing
This one https://app.orgmeter.com/login - contains 3 fields, all required, but auto-fill works only for Username and Password, but not Company.
https://www.masterpass.com.ua/Login.aspx? - in MX5 auto fill phone/password works, in MX6 does not.
Save form / Fill form in MX5 has also stored/read values in Passkeeper. Isn't it? But it stored more fields (e.g. all 3 - username, password, company).
Also, Magic Fill in MX5 allowed to not fill passwords automatically ("Manual" option). It was convenient and more secure.