Dublicating course

Hello, congrats for this nice plugin

After duplicating a course with its curriculum and trying to edit the new course, the curriculum disappears. Is it because I cannot have 1 lesson assigned in two or more courses?
Actually I am trying to create a paid course and give its first section as a free course, so I duplicate the course and keep the only the section I want. But when updating the course page, curriculum is lost. Is there a better approach for this?

thank you

https://wordpress.org/plugins/learnpress/