Symptoms
When updating your system packages via WHM >> System Update, the text box remains empty, and packages are not updated.
Description
This issue is caused by the file /usr/local/cpanel/logs/packman/current_build existing, commonly leftover by a previous interrupted EasyApache build.
Workaround
Delete or move aside the /usr/local/cpanel/logs/packman/current_build file:
mv -v /usr/local/cpanel/logs/packman/current_build /usr/local/cpanel/logs/packman/current_build.BAK