Without your setup and data I cannot be sure what is going on. But, my suggestion is to set the Minimum and Maximum properties of the axis so that they match the range you expect. Note that by default the chart axis will calculate its range based on the plotted data. This is why the last 3 dates you expect are not presented on the axis.
Can you please test the Minimum and Maximum properties and let me know how it goes? If this doesn't help I would ask you to send me some runnable code that demonstrates your set up and also a drawing of the expected result (with the bars). This way I can think of a suitable solution for your scenario.
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