http://jsfiddle.net/dLbyj4e7/
As you can see from the data points, the date starts from 2015-01-01 but the label starts from 2014-12-31. The X axis legend is generated properly, but not the label. This seems to be an issue with the actual label, if you manually assign a label using a new Date object, it is still a day behind; example in the last 3 bars in http://jsfiddle.net/dLbyj4e7/1/
I only tested this with columns and line chart types, but this doesn’t seem to be a chart-specific problem.
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