Ctrl/Cmd-Shift-X doesn't work when 1Password is locked

Thank you for getting back to me mikeho, I thought it may have been an integration issue but that rules that out if you don't have the 1Password app installed. You're right, you don't need that setting enabled.

Can you right click on the 1Password icon in your browser toolbar and choose Settings then scroll down to the 'Shortcuts' section and choose 'Change on Extensions page'. Do you see the correct shortcut (⇧⌘X) allocated to activate the extension?