ListAdapter does not update item in RecyclerView: data changes but UI does not redraw

Hello everyone! I'm a beginner in Kotlin and Android development. I'm using ListAdapter for RecyclerView, but I've encountered a strange problem: when I change data in the list and call submitList(), the items are not updated on the screen. Here is my code: ```kotlin data class Item(val id: Int, var title: String, var isCompleted: Boolean) class ItemDiffCallback : DiffUtil.ItemCallback() { override fun areItemsTheSame(oldItem: Item, newItem: Item): Boolean { return oldItem.id == newItem.id } override fun areContentsTheSame(oldItem: Item, newItem: Item): Boolean { return oldItem == newItem } } class ItemAdapter : ListAdapter(ItemDiffCallback()) { // ... ViewHolder and bind } // In Activity val items = mutableListOf( Ite