So let's say we have a nesting of Parent A and Child B.
If you have some data already and then click "Add parent A" then it will show an extra form to fill out Parent A (correct), but it will also add a form to the last "Parent A item" already present for filling out child B (incorrect).
Also if you then add a Child B from the newly created Parent A form, it will add the Child B form to the previous (pre-existing) Parent A item, not the new Parent A item...
So let's say we have a nesting of Parent A and Child B.
If you have some data already and then click "Add parent A" then it will show an extra form to fill out Parent A (correct), but it will also add a form to the last "Parent A item" already present for filling out child B (incorrect).