I tried your code and it works to me. Probably we're misunderstanding each other.
The 'default_state' => 'collapsed' makes sure when you create a new post, the group will be collapsed.
When you open a group to enter data, its state will be reserved (with 'save_state' => true). When you clone a group, the previous is remained (so if the last clone is expanded, then the new clone is expanded and vice versa).