SUMMARY
After adding credentials to an OpenVPN connection configuration, if one selects "Store password for this use only (encrypted)" and clicks Apply, the password is not saved (e.g., in the designated, open kwallet). This is a recent change in behavior.

STEPS TO REPRODUCE
1. System Settings > Connections
2. Pick an existing OpenVPN connection (or import a *.openvpn) that needs a password but the password field is empty.
3. Enter the valid username and password in the respective fields.
4. Select "Store password for this use only (encrypted)" under the password field.
5. Click the Apply button.
6. Close System Settings.
6. Try connecting to the OpenVPN connection.

OBSERVED RESULT
Dialog appears asking for password. Returning to the configuration panel of the connection in System Settings > Connections shows an empty password field.

EXPECTED RESULT
The password dialog should not appear and the connection should be attempted with the saved credentials. The username and password fields in connection configuration panel should persistently show the credentials.

SOFTWARE/OS VERSIONS:
OS: Kubuntu 18.04
(available in About System)
KDE Plasma Version: 5.12.9
KDE Frameworks Version: 5.47.0
Qt Version: 5.9.5

ADDITIONAL INFORMATION
This is new behavior. Saving the password used to work correctly until recently.

Related: Bug #396795 – This addresses a bug in a later version of NetworkManager (1.20) in Ubuntu 19.10 and higher. This bug report is for Kubuntu 18.04 (LTS).