When you switch the package type from "uploaded package " to "External SCORM manifest", the uploaded package remains after you have deleted it.
It looks like one uploaded file is required. You just can upload a new package.
1) Add a new activity Scorm with package type "uploaded package"
2) Update the activity
- delete package
- switch type to "External SCORM manifest"
- Instert URL
3) Update Scorm activity
- switch type to "uploaded package"
- old package is still there
This behavior is problematic if the packages should not be longer into the course due to their size.