For the site below the auto fill/submit function launched via the extension icon and the keyboard (command /) does not work. If I copy the password to the clipboard (via extension) and paste into the password field and manually submit the login succeeds. I have had no problem with other sites.
The site is the Social Security Administration: https://secure.ssa.gov/RIL/SiView.do
1Password Version: 6.6.1
Extension Version: 4.6.3
OS Version: macOS 10.12.3
Sync Type: Wireless