Error during uninstall - Fail to remove environment variables (system+persistent)

During complete removal of the components, the installer prompt an error popup and fails in removing system environment variables created during installation.

The code in the component script is:

component.addElevatedOperation("EnvironmentVariable", "QT_PLUGIN_PATH", "@TargetDir@\\lib\\system\\qt
plugins", true, true); 

and running the uninstall with -v option, it gives:

[3929] undo operation= "EnvironmentVariable"
[3929] undo lib.system.qt operation: EnvironmentVariable
[3929]  - arguments: QT_PLUGIN_PATH, C:/EPC_Test/lib/system/qt/plugins, true, true
[3931] Done
[3931] Created warning message box "installationErrorWithRetry": "Installer Error", "Error during uninstallation process:\n"