To reproduce:
1. Go to a course
2. Go to the settings page of the course
3. Activate the Flexible Sections course format (needs to be installed)
4. Add a few activities to the course in different sections and sub sections.
5. Click the "Edit" drop down menu.

Now on some menus extra "Copy to Sharing Cart" menu items are added. Please check this screenshot:
https://www.screencast.com/t/VPxnxIqLTN

I created this pull request to fix the bug:
https://github.com/donhinkelman/moodle-block_sharing_cart/pull/24