The QR code scanner works fine for me in the Chrome 1PasswordX extension on Windows but the Mac Safari version consistently never works. I choose Edit and click the QR icon for the OTP field, the screen capture window shows up and I can move it to get the green edges but then nothing happens. 100% reproducible.
Version 7.2.4 (70204000)
When you get the green edges, it should close and put the URL should appear in the field where you clicked the QR icon. You did mention "Safari" - do you mean when opening 1Password mini from the icon in Safari? Does it work when editing the item from the main 1Password window?