Thank you for testing. I just saw that (my) user error could have caused problems as well, because of different backup archive types: The cron based backups are saved as tar.gz while the manual backups are saved as zip files.
why did you decide to have 2 different backup filetypes?
this means, that a cron backup can not be used for manual restauration, because if we manually replace the manual backup file with the cron backup file, the file won't be extracted because of an file type error.
also why is a cron backup named "web_domain.com_date_time" while a manual backup is called only "domain.com_date_time"?
i think by using the same naming structures and zip files only, the restoration process could be made more flexible in future releases. in general i think an easy backup module to down and upload of backups that can be easily restored later on would be a great addition to the panel.