I have the current beta version of 1Password installed [6.5.BETA-21 (650021)] on a MacBook Pro running 10.12.1 Beta (16B2338c) and Safari Technology Preview [Release 14 (Safari 10.1, WebKit 12603.1.6.0.2)].
The browser extension no longer functions and going to a web site in this browser no longer links to 1Password. I've tried reinstalling 1Password, and installing the browser extension from the download (it doesn't install) and from the Gallery (where it installs but doesn't work).
Similar behaviour is seen using the current Chrome browser.
Before going to the business of deleting preferences and so forth, I wondered if this was a known problem.
1Password Version: 6.5.BETA-21 (650021)
Extension Version: 4.6.2.b1`
OS Version: 10.12.1 Beta (16B2338c)
Sync Type: DropBox