The bug in Google Apps Script: sheet.getCharts() and embedded Bubble Chart

I created a Bubble Chart manually on the spreadsheet and I can see it. But I can't reach it by script. sheet.getCharts() doesn't return my Bubble Chart (but I see other charts)

/* OnOpen Trigger modifying an existing (embedded) chart */
function onOpen (e) {
  try {
    var ss = SpreadsheetApp.getActiveSpreadsheet();
    var sheet = ss.getSheets()[0];
    var bubbleChart = null;

    var charts = sheet.getCharts();

    debugger

    for (var i in charts) {
      Logger.log(charts[i].getOptions().get('title'));
    }

  } catch (err) {
    Logger.log(err.toString());
  }
}