NCP v1.21 error upgrading to NC 18.0.1

When trying to upgrade to NC18.0.1 I get the follwing log / error message

Running nc-update-nextcloud
Current   Nextcloud version
Available Nextcloud version 18.0.1
Download Nextcloud 18.0.1...
Back up current instance...
check free space...
Maintenance mode enabled
backup database...
backup files...
backup /var/www//nextcloud-bkp_20200315_1584287334.tar.gz generated
Maintenance mode disabled
Install Nextcloud 18.0.1...
Restore apps...
 * calendar
 * contacts
 * files_texteditor
 * gallery
 * news
 * nextcloudpi
 * notes
 * previewgenerator
 * previewgenerator.orig
 * tasks
Fix permissions...
Nextcloud is not installed - only a limited number of commands are available

  Command "upgrade" is not defined.

Runnning system is running without problems behind Traefik reverse proxy on port 8443.

Try again with 18.0.2