I signed into yahoo.com w/ a bogus account, and it rejected my password, but chrome offered to save it. Yahoo has a pretty convoluted flow.

vers: 70.0.3521.2 (linux)

Flow:
  yahoo.com -> click "sign in"
  login.yahoo.com/config/login... -> type bogus email, next
  login.yahoo.com/account/challenege/recaptcha... -> click box
  login.yahoo.com/account/challenge/password... -> type bogus password
  login.yahoo.com/account/challenege/recaptcha... ->
    -> Chrome pops up the "save this password dialog
    -> I click captcha box
  login.yahoo.com/accounts/challence/password.. "Invalid password"