Configurations in /etc/hosts file unexpectedly become wrong

Issue

• After setting new hostname, IP address and alias by system-config-network, the configuration in /etc/hosts file is deleted or become wrong.

Verify the current content in /etc/hosts file

1. # cat /etc/hosts
127.0.0.1 www.test.co.jp www localhost.localdomain localhost

Add a configuration by system-config-network

2. # system-config-network

Host Tab -> New Tab

192.168.0.1 www.test.co.jp www  <-add

See the contents in /etc/hosts file

3. # cat /etc/hosts
127.0.0.1                      <-'hostname' and 'alias' are missed
192.168.0.1 www.test.co.jp www

or
                               <-'IP address', 'hostname' and 'alias' are all deleted
192.168.0.1 www.test.co.jp www