I know that, so I wasn't surprised when 1Password became increasingly messy. It had multiple logins with different passwords and I don't think it was synchronizing correctly from desktop to iPhone. I decided to start over.
Fortunately I've never trusted 1Password, so the "source of truth" for my passwords is a 15yo FileMaker Pro database with about 1,600 records. It's not only a credential story, it's a history of the WWW (as we used to call it.) So I deleted everything in 1Password desktop and did a sync to my iPhone. There's no UI indicator that sync is happening, but shortly thereafter there were about 3,200 records on my iPhone and 1,600 on my desktop.
So after some messing about I hit the "reset" button in 1Password/iPhone and tried to sync with the OS X app overwriting the iPhone.
Nothing happened. There was no error message, but clicking on the sync button didn't do anything.
Google eventually took me a to a very long 1Password tech support thread. It's sad reading -- clearly 1Password is in trouble. Towards the end I saw something promising ....
How to Sync 1Password on Mac to my iPad - AgileBits Forums: "defaults write ws.agile.1Password ShowWiFiSyncAuthAutomatically -bool YES"
Terminal hacks usually work. This one did. When next I started the desktop app I got the dialog for entering my 'secret codes' and I was able to sync. Everything is clean for the moment.
Obviously, 1Password doesn't meet my tests. My guess is that their too ambitious for their technical abilities. They've tried to make synchronization automatic and invisible, but they failed to provide a manual option for when things go wrong. Sync is Hell, things will go wrong.
What I really want is the old FileMaker Mobile app for the Palm. There's nothing like it now; the closest today is Bento's ability to sync desktop and iOS device. I'd go for Bento, but there's no iOS encryption option. So it doesn't work.
For now, 1Password is my least bad option. I can't recommend it for anyone else however.