I'm running the 1.6.7 beta on Firefox Developer Edition 60.0b12. I'm using a Retina MacBookPro, 15", Late 2013, 2 GHz Intel Core i7, 16GB RAM, OS X 10.13.2. Autofill of the login name works fine, but the password field then only gets one character of a 30 character password. The page URL is https://online.citi.com/US/login.do?JFP_TOKEN=OH6AK1R1.
Here is a screenshot:
1Password Version: 1Password X Beta
Extension Version: 1.6.7
OS Version: 10.13.2
Sync Type: N/A