Hi, I don't know if I should post this here, or email 1PW support, so if this is the wrong place please delete.
I was browsing your doco and found this useful page https://support.1password.com/explore/extension/
I clicked the link under "Fill two-factor authentication codes" which points to the page https://support.1password.com/one-time-passwords/
Kaspersky blocks this page with the message "Threat of Data Loss". I elected to allow access from Firefox browser and later checked the Kaspersky log - screenshot below.
Allowing this seems to be browser dependent - I later tried from Chrome and got the same "blocked" message
I am running a windows 10 desktop with Kaspersky Internet Security 2018 version 19.0.0
1Password Version: Not Provided
Extension Version: Not Provided
OS Version: Not Provided
Sync Type: Not Provided