Data not beeing applied to correct category with DateTime

[Ragnar Smári]

I have a chart where I want to display data troughout the day.
I created categories for each hour of the day in the format "HH:00".
The datetime property in the data is also in the format of "HH:00".
But when the chart is rendered the data is put in the wrong category.

For example if the first datapoint is at 08:00 then that datapoint would be put in the category 00:00.
Am I missing something working with Categories or is this a bug?