The collapsible groups have collapsed / expanded state. You can set the default state via 'default_state' => 'collapsed' and make the group saves its state with 'save_sate' => true.
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).
I think that new clone should be open by default. At least after clicking to add more. It's strange that user clicks add more and then he gets collapsed group.
Ah, as I explained in the previous reply, the new cloned group will inherit the current state of the last clone. So if the last one is collapsed, users will get a new collapsed one.
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