I have a page in an app that displays all sorts of ticket metrics from several different ticketing systems we use. I use the same function to build each of the charts and display them:

function drawChart(chartData, chartStyle, chartTitle, chartSpanID) {
  var data = new google.visualization.DataTable();
  
  data.addColumn('string', 'Hour');
  data.addColumn('number', 'Tickets');
  data.addRows(chartData);
  
  if(chartStyle == "column"){
    var chart = new google.visualization.ColumnChart(document.getElementById(chartSpanID));
    var options = {title:chartTitle,chartArea: {left: 30, top:20, bottom:30, right:10},animation:{startup: true, duration:2000}}
    };
  
  if(chartStyle == "pie"){
    var chart = new google.visualization.PieChart(document.getElementById(chartSpanID));
    var options = {title:chartTitle, 
                   chartArea:{left: 0, top:20, bottom:10, right: 0},
                   is3D: true,
                   sliceVisibilityThreshold: .01,
                   animation:{startup: true,easing: 'in', duration:1000},
                   pieResidueSliceLabel: "Other( < 1%)"};
};
chart.draw(data, options);

}

This works for 13 of the 14 charts displayed on the page. 8 Columns and 5 out of 6 pie charts all display perfectly. One of the pie charts will ONLY display if I draw the chart a second time.

function drawChart(chartData, chartStyle, chartTitle, chartSpanID) {
  var data = new google.visualization.DataTable();
  
  data.addColumn('string', 'Hour');
  data.addColumn('number', 'Tickets');
  data.addRows(chartData);
  
  if(chartStyle == "column"){
    var chart = new google.visualization.ColumnChart(document.getElementById(chartSpanID));
    var options = {title:chartTitle,chartArea: {left: 30, top:20, bottom:30, right:10},animation:{startup: true, duration:2000}}
    };
  
  if(chartStyle == "pie"){
    var chart = new google.visualization.PieChart(document.getElementById(chartSpanID));
    var options = {title:chartTitle, 
                   chartArea:{left: 0, top:20, bottom:10, right: 0},
                   is3D: true,
                   sliceVisibilityThreshold: .01,
                   animation:{startup: true,easing: 'in', duration:1000},
                   pieResidueSliceLabel: "Other( < 1%)"};
};
chart.draw(data, options);
chart.draw(data, options);
}

The data is delivered correctly, all calls are made through google.charts.setOnLoadCallback, it all works just fine once called again... so why is it only working on the second call? Why just the one chart that doesn't display as expected? What have I missed?