You might encounter WHM showing "UNKNOWN" at the top next to the cPanel version number when logging in, this can occur due to the RPM database being corrupted and you must run the commands below to correct restore the OS Information correctly.
From SSH run the following commands
This script will help correct most RPM Database issues.
And this will correct the "UNKNOWN" section at the top of WHM
You will need to restart cPanel to make sure the changes take effect and are viewable