I use 1Password (version 6.2.2) for iPhone 5S (iOS 9.2.1) and 1Password (version 6.0.2) on a MacBook Pro (El Capitan 10.11.3). Whole devices syncing by the same Wi-Fi. iPhone and MBP mostly are in one the same Wi-Fi.
To this day, everything worked great! Today I wanted to change Master Password. I changed them first on the MBP (https://support.1password.com/change-master-password/mac.html). And now as I enter it on 1Password MBP I've included a new Master Password already up and everything is OK. But the iPhone is still active old Master Password:( I have a questions: What am I doing wrong or what should I change in the action / password MasterPassword do that on the iPhone also has changed? Well but I will not manually change a Master Password on the iPhone because it makes no sense...
Please Help because I ran out of ideas and just probably erase 1Password from my iPhone 5S and install it again . Maybe it will helps
1Password Version: 6.0.2
Extension Version: Not Provided
OS Version: El Capitan 10.11.3
Sync Type: Wi-Fi