Fix stacked-100-m update error

src/shape.line.js

@@ -324,6 +324,7 @@ c3_chart_internal_fn.updateCircleY = function () {
         lineIndices = $$.getShapeIndices($$.isLineType),
         getPoints = $$.generateGetLinePoints(lineIndices);
         $$.circleY = function (d, i) {
+            d = $$.updateValues(d)[i];
             return getPoints(d, i)[0][1];
         };
     } else {