On Kubuntu 1Password Firefox extension doesn't unlock when native 1Password application (installed via apt) is unlocked. Maybe related to KDE, as it works with plain Ubuntu?
Thanks for leaving us a review! It's possible there might be something going on with your install of Kubuntu that's preventing the 1Password Extension from talking to the desktop app. If you'd send us a message at support+linux@1password.com we'd be happy to take a closer look at this with you.
