Dashlane completion does not work as intended on the login page

[fishilico]

A user using Dashlane to store his credentials reported that Dashlane filled the "login or email" field with "Firstname Lastname" instead of the username (or an address), on the login page. The field seems to be mis-identified, and this may be caused by something in the HTML code.

Is it possible to modify the code of the login form in order to fix Dashlane's autofill feature? Does this issue affect other password managers, like LastPass?