I had callbacks set up on several pages in order to access the HighCharts obj.options.legend.reversed = true feature in order to reverse the order of the legend on my charts. It suddenly stopped working in the last few weeks on every page over multiple charts despite not changes in the site. The charts still work fine, so the number is correct, just the callbacks don't work. I'm using the following code, which again worked before and follows the sample on your site (see "Related URL). It now doesn't have an effect on any aspect of the chart, i.e. the background color isn't set either. Do you have any suggestions for why this would stop working? 

<script type="text/javascript">
jQuery(window).load(function(){
    if( typeof wpDataChartsCallbacks == 'undefined' ){ wpDataChartsCallbacks = {}; }
    wpDataChartsCallbacks[2] = function(obj){
obj.options.legend.reversed = true;
        obj.options.chart.backgroundColor = '#F7F7F7';
        obj.options.chart.zoomType = 'x';
        obj.options.chart.panning = true;
        obj.options.chart.panKey = 'shift';
        obj.options.tooltip = {
            formatter: function () {
            var s = '<b>' + this.y + '</b>';
            return s;
            }
        }
    }
});
</script>

[wpdatachart id=2]

That worked, thank you! 

You may want to update the sample code on your site at the page I referenced to reflect this.