Please make sure that you are logged in with the same Balance credentials (same email and same app version) on both devices. You can check this by going to Profile > Settings and verifying that the email at the top of the page and the version number at the bottom of the page match on both devices.
Your device automatically creates a backup when you are connected to a strong Wi-Fi network with full bars and you complete a meditation session.
If you happen to meditate offline and then reconnect to our servers, it might take a bit for the app to update.
If you recently updated to the latest Balance version, you might need to log out and sign back in to access the latest data.