The vertical position was based on index in sorted array. It must be done by stored order

src/diagrams/gantt/ganttRenderer.js

@@ -189,6 +189,9 @@ export const draw = function(text, id) {
       })
       .attr('height', theBarHeight)
       .attr('transform-origin', function(d, i) {
+        // Ignore the incoming i value and use our order instead
+        i = d.order;
+
         return (
           (
             timeScale(d.startTime) +