When using Safari on MacOS 10.14.2 running 1Password 7 Version 7.2.3.BETA-7 (70203007), as well as previous beta and stable releases, on a Mac mini, the following occurs:
The only way to fix this is to manually launch 1Password 7, enter the password, and reload the Safari page.
1Password Version: 7.2.3.BETA-7 (70203007)
Extension Version: 7.2.3.BETA-7
OS Version: 10.14.2
Sync Type: iCloud
NOTES: I believe this to be a duplicate of similar issues such as: https://discussions.agilebits.com/discussion/98926/1password-7-version-7-2-3-beta-2-70203002-safari-extension-not-working
I am submitting a support request with the diagnostic log at this time as well.