MaintenanceTool does not work if started as root

Starting the maintenance tool with su/sudo yields:

[14] Warning: Failure to read packages from /opt/Qt/components.xml.
[14] Critical: Operations missing for installed packages ()
[14] Critical: Orphaned operations ("qt", "qt.tools.ninja", "qt.tools", "qt.tools.qtcreator", "qt.tools.maintenance", "qt.tools.cmake")
[15] Critical: Your installation seems to be corrupted. Please consider re-installing from scratch, remove the packages from components.xml which operations are missing, or reinstall the packages.