Adding data from parent recyclerview adapter and removing data from child recyclerview adapter

I have a nested recyclerview. Parent recyclerview adapter can add a data to child by a button, then child recyclerview adapter can remove a data in child by a button. The preview is like below.

Adding data seems fine, but when removing data i got index out of bound. I have called notifyDataSetChanged() in add or remove function.

My parent adapter code :

class FormPlanParentAdapter :
    RecyclerView.Adapter<FormPlanParentAdapter.ViewHolder>() {

    private val data: MutableList<MutableList<ItemPlan>> = mutableListOf()

    private val viewPool = RecyclerView.RecycledViewPool()

    fun setData(newData: List<MutableList<ItemPlan>>) {
        data.clear()
        data.addAll(newData)
        notifyDataSetChanged()
    }

    fun getData(): String = Gson().toJson(data)

    override fun onCreateViewHolder(
        parent: ViewGroup,
        viewType: Int
    ): ViewHolder {
        return ViewHolder(
            LayoutInflater.from(parent.context).inflate(R.layout.item_plan_parent, parent, false)
        )
    }

    override fun getItemCount(): Int = data.size

    override fun onBindViewHolder(
        holder: ViewHolder,
        position: Int
    ) {
        val parent = data[position]
        val childLayoutManager = LinearLayoutManager(
            holder.recyclerView.context,
            LinearLayoutManager.VERTICAL,
            false
        )

        val childAdapter = FormPlanChildAdapter(parent, object : PlanParentCallback {
            override fun deletePlan(position: Int) {
                parent.removeAt(position)
                notifyDataSetChanged()
            }
        })

        holder.recyclerView.apply {
            layoutManager = childLayoutManager
            adapter = childAdapter
            setRecycledViewPool(viewPool)
        }

        holder.textView.text = "Hari ke ${position + 1}"

        holder.imageButton.setOnClickListener {
            parent.add(ItemPlan())
            notifyDataSetChanged()
        }
    }

    inner class ViewHolder(itemView: View) : RecyclerView.ViewHolder(itemView) {
        val recyclerView: RecyclerView = itemView.rv_plan_child
        val textView: TextView = itemView.tv_days_of
        val imageButton: ImageButton = itemView.ib_add
    }

    interface PlanParentCallback {
        fun deletePlan(position: Int)
    }

}

My child adapter code :

class FormPlanChildAdapter(
    private val children: List<ItemPlan>,
    private val callback: FormPlanParentAdapter.PlanParentCallback
) :
    RecyclerView.Adapter<FormPlanChildAdapter.ViewHolder>() {

    override fun onCreateViewHolder(
        parent: ViewGroup,
        viewType: Int
    ): ViewHolder {
        return ViewHolder(
            LayoutInflater.from(parent.context).inflate(R.layout.item_plan_child, parent, false)
        )
    }

    override fun getItemCount(): Int = children.size

    override fun onBindViewHolder(
        holder: ViewHolder,
        position: Int
    ) {
        val child = children[position]
        holder.etPlan.setText(child.plan)
        holder.etPlan.doAfterTextChanged {
            children[position].plan = it.toString()
        }

        if (position == 0) {
            holder.ibDelete.invisible()
        } else {
            holder.ibDelete.visible()
        }

        holder.ibDelete.setOnClickListener {
            if (children.size > 1) {
                callback.deletePlan(position)
            }
        }
    }


    inner class ViewHolder(itemView: View) : RecyclerView.ViewHolder(itemView) {
        val etPlan: EditText = itemView.et_plan
        val ibDelete: ImageButton = itemView.ib_delete
    }
}

Any help appreciated, thank you.

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