iCloud Keychain Items Missing from List, But Already Exist When Adding

There are items not showing in my list of iCloud keychain passwords, yet when I try to add them manually it says they already exist and the only option is to click "Done". The URL it shows in the alert about the "existing" item is identical to the one I'm trying to add, yet I can't find the item anywhere in the list and I can't add it, either. Since it doesn't show anywhere in the list I can't delete it and re-add it. What gives?