Atlaskit Table-tree error cannot add sub-item in level 2 of table-tree

My intent is to add sub-item in table-tree by input dynamic data as input textfield (link codesandbox)
success add sub-item at level-1

but facing error at level-2

I cannot deep dive into the source code to find the root cause

Is there anyway to get the source code of Atlaskit component?
or any advice for my case

Thank you!