Chrome Version       : 67.0.3389.0
OS Version: OS X 10.13.3
URLs (if applicable) : https://es.khanacademy.org/login

What steps will reproduce the problem?
1. Visit https://es.khanacademy.org/login
2. Try to save a password there (use key icon in the Omnibox)
3. Reload

What is the expected result?
Form gets autofilled.

What happens instead of that?
Nothing is autofilled. Password can be filled on demand.

The reason is that the page wraps each <input> element in a separate <form>. Hence Chrome sees one form which has only a text field (no password) and another one which only has a password. It can remember a value for the password, but will not fill the username.