Problem to stack some factors in the graphic

[brolin]

Hi, first i want to thank you for create this widget.

I have trouble to create a graphic with step interpolation and offset zero for 19 variables in a period of 365 days. Look at the result here http://bibliolabs.cc/visualizaciones/FlujoUsuarios1/

I took the expand part from the streamgraph function and seem that for each category with the problem the result length after the expansion is different. I get lengths of 365 for some categories anothers of 366 and one of 369. I suspect that the issue is there. ¿Did you see something similar before? ¿Any clue?

Thanks