There is not much more to tell. When I enter my login in the browser (Safari) I almost every time get a message to sign in to iCloud since the session has expired. This has not been the case in previous versions.
1Password Version: 1Password 6 Version 6.3 (630032) AgileBits Store
Extension Version: 4.5.6
OS Version: 10.11.5
Sync Type: iCloud
Referrer: forum-search:icloud signin problems with latest version