Hallo Christian,
Please see note 1587566 where it states:
- When uninstalling with the command line options "/uninstall /all", the event
scripts of installed packages, which are defined to run on uninstall, are now
executed.
Recommend to update your installation server to the latest nwsapsetup patches referenced in the attached note http://service.sap.com/sap/support/notes/1587566
Best Regards,
Jude