DividerItemDecoration artifacts when updating items

MainActivity.java

package com.company.user.recyclerviewdecorationtest;

import android.graphics.Rect;
import android.support.v7.app.AppCompatActivity;
import android.os.Bundle;
import android.support.v7.widget.DividerItemDecoration;
import android.support.v7.widget.LinearLayoutManager;
import android.support.v7.widget.RecyclerView;
import android.view.Menu;
import android.view.MenuItem;
import android.view.View;
import android.view.ViewGroup;
import android.widget.TextView;

import java.util.Arrays;
import java.util.Random;

import static android.support.v7.widget.RecyclerView.NO_POSITION;

public class MainActivity extends AppCompatActivity {
    public static class ViewHolder extends RecyclerView.ViewHolder {
        public ViewHolder(View itemView) {
            super(itemView);
        }
    }

    private String[] testList;
    private RecyclerView.Adapter<ViewHolder> modelAdapter;

    private static final String alphabet = "0123456789 ABCDEFGHIJKLMNOPQRSTUVWXYZ abcdefghijklmnopqrstuvwxyz";
    private static String[] generateTestData() {
        Random random = new Random();

        int count = 3;// + random.nextInt(100);
        String[] dataList = new String[count];
        for (int i = 0; i < count; i++) {
            int length = 10 + random.nextInt(100);
            StringBuilder stringBuilder = new StringBuilder(length);

            for (int j = 0; j < length; j++) {
                stringBuilder.append(alphabet.charAt(random.nextInt(alphabet.length())));
            }

            dataList[i] = stringBuilder.toString();
        }

        return dataList;
    }

    private static void truncateTestDataItems(String[] dataList) {
        for (int i = 0; i < dataList.length; i++) {
            if (!dataList[i].isEmpty()) {
                dataList[i] = dataList[i].substring(0, dataList[i].length() - 1);
            }
        }
    }

    @Override
    protected void onCreate(Bundle savedInstanceState) {
        super.onCreate(savedInstanceState);
        setContentView(R.layout.activity_main);

        testList = generateTestData();

        RecyclerView recyclerView = (RecyclerView) findViewById(R.id.recycler_view);
        recyclerView.setHasFixedSize(true);

        LinearLayoutManager layoutManager = new LinearLayoutManager(this, LinearLayoutManager.VERTICAL, false);
        recyclerView.setLayoutManager(layoutManager);

        DividerItemDecoration itemDecoration = new DividerItemDecoration(this, layoutManager.getOrientation());
        recyclerView.addItemDecoration(itemDecoration);

        modelAdapter = new RecyclerView.Adapter<ViewHolder>() {
            @Override
            public ViewHolder onCreateViewHolder(ViewGroup parent, int viewType) {
                View root = getLayoutInflater().inflate(R.layout.list_item, parent, false);
                return new ViewHolder(root);
            }

            @Override
            public void onBindViewHolder(ViewHolder holder, int position) {
                TextView textView = (TextView) holder.itemView.findViewById(R.id.text_view);
                textView.setText(testList[position]);
            }

            @Override
            public int getItemCount() {
                return testList.length;
            }
        };
        recyclerView.setAdapter(modelAdapter);
    }

    @Override
    public boolean onCreateOptionsMenu(Menu menu) {
        menu.add("NEW").setShowAsAction(MenuItem.SHOW_AS_ACTION_ALWAYS);
        menu.add("PAYLOAD").setShowAsAction(MenuItem.SHOW_AS_ACTION_ALWAYS);
        menu.add("EMPTY").setShowAsAction(MenuItem.SHOW_AS_ACTION_ALWAYS);

        return super.onCreateOptionsMenu(menu);
    }

    @Override
    public boolean onOptionsItemSelected(MenuItem item) {
        if (item.getTitle().equals("NEW")) {
            testList = generateTestData();
            modelAdapter.notifyDataSetChanged();

            return true;
        }

        if (item.getTitle().equals("PAYLOAD")) {
            truncateTestDataItems(testList);
            modelAdapter.notifyItemRangeChanged(0, modelAdapter.getItemCount(), "payload");

            return true;
        }

        if (item.getTitle().equals("EMPTY")) {
            truncateTestDataItems(testList);
            modelAdapter.notifyItemRangeChanged(0, modelAdapter.getItemCount());

            return true;
        }

        return super.onOptionsItemSelected(item);
    }
}