The redrawChart method in the Chart class does not work after refreshing the data store if there are a fewer intervals of time in the TimeAxis or categories in the CategoryAxis than there were before.
The drawSeries method in the BarSeries class appears to create new or reuse bar sprites, but does not remove ones that are no-longer needed / wanted.
This results in a lot of stale bars / columns being left behind (see attached ChartRedrawIssueScreenShot.png).
I tried the delete method in the Series class to no avail.
To recreate this error, run the attached ColumnChart_RedrawIssue.txt and click the refresh button after the chart has finished rendering for the first time.
This is probably a system wide issue across all series types.