I saved a login for myloancare.com and use the Safari and Chrome browser extensions to fill the username and password. When I click the SUBMIT button, the login fails. I then copy/paste the password saved in 1Password for this website and hit SUBMIT again and it works.
I have had this exact experience on web sites that restrict the number of characters in passwords when I have created one longer than what is allowed by the site. There is a discussion somewhere in these forums where @MikeT said that the process of transferring the the password directly from 1Password is different from how it works with cut and paste, but I don't remember the details. Is it possible that you are running into the same issue? I have at least two sites where I've experienced this. When I reduced the password length to the site's limit, it then began to work properly.