MaterialUtils.java

// ...

    public static void fixToolbarOverflowButton(final Activity activity) {
      if (Build.VERSION.SDK_INT >= 21) {
        // the problem occurs only on LOLLIPOP when using native Toolbar and Action Bar
        try {
          final int abId = activity.getResources().getIdentifier("android:id/action_bar", null, null);
          final Toolbar toolbar = (Toolbar) activity.getWindow().getDecorView().findViewById(abId);
          final int moreId = activity.getResources().getIdentifier("android:string/action_menu_overflow_description", "string", null);

// copy the drawable from appcompat-v7 library if you don't use it OR use the framework one if it's available
          final Drawable d = getDrawableWithColorControlNormal(toolbar.getContext(), R.drawable.abc_ic_menu_moreoverflow_mtrl_alpha);

          toolbar.getViewTreeObserver().addOnGlobalLayoutListener(new ViewTreeObserver.OnGlobalLayoutListener() {
            @Override
            public void onGlobalLayout() {
              final String moreString = activity.getString(moreId);
              final ArrayList<View> out = new ArrayList<>();
              toolbar.findViewsWithText(out, moreString, View.FIND_VIEWS_WITH_CONTENT_DESCRIPTION);
              if (out.isEmpty()) return;
              final ImageButton moreButton = (ImageButton) out.get(0);
              moreButton.setImageDrawable(d);
              Util.View.removeOnGlobalLayoutListener(toolbar, this);
            }
          });
        } catch (Exception ex) {
          // this is a pretty hacky solution, anything can go wrong really
          ex.printStackTrace();
        }
      }
    }
    
    /**
     * Read colorControlNormal (on API < 21) or android:colorControlNormal (on API 21) from theme and apply it to specified drawable.
     */ 
    @TargetApi(Build.VERSION_CODES.LOLLIPOP)
    public static Drawable getDrawableWithColorControlNormal(Context context, @DrawableRes int drawableId) {
      TypedArray ta = context.obtainStyledAttributes(new int[]{API_21 ? android.R.attr.colorControlNormal : R.attr.colorControlNormal});
      int c = ta.getColor(0, Color.BLACK);
      ta.recycle();
      Drawable d = context.getApplicationContext().getResources().getDrawable(drawableId);
      return tintDrawable(d, c);
    }

    /**
     * Paint supplied Drawable with supplied color.
     */
    public static Drawable tintDrawable(Drawable d, int c) {
      PorterDuffColorFilter cf = new PorterDuffColorFilter(c, PorterDuff.Mode.SRC_IN);
      d.mutate().setColorFilter(cf);
      return d;
    }

// ...

MyActivity.java

// ...

public void onCreate(Bundle savedInstanceState) {
  // ...
  
  if (savedInstanceState == null) {
    // since the bug occurs only on first run
    // let's apply a fix only in that case
    // subsequent runs or screen rotations are ok
    MaterialUtils.fixToolbarOverflowButton(this);
  }
}

// ...