Percentages in Small Multiples Not Accurate

Hello,

I have a clustered column visual using small multiples where I'm trying to represent the counts in the columns as percentages, however the perecentages are not accurate when I choose "Show value as Percent of grand total" in the Y-axis values.  The visual is meant to show a 6 week trend.  I've provided screenshots of the visual as it is currently, and also a screenshot of the attributes I'm using for the axes, legend and small multiples.

In the first screenshot the counts are accurate.

In the second screenshot is when I choose to show the values as percent of grand total, and this is where the results are inaccurate.

These are the attributes I'm using in the visual.  None of these are measures or calculated columns.

I'm unsure why the visual is behaving this way.  Any help is much appreciated.

Thanks,

David