(NaN) error bug?

Hi,

I have the latest build of Desktop and a column chart. I added the below Measure for a Tooltip:

Revit Version =

if (DISTINCTCOUNT(vwRevitDocumentSession[RevitVersionName])<>1,

"Error",

VALUES(vwRevitDocumentSession[RevitVersionName]))

I get the "Chart data contains not a number (NaN) values"

The Tooltip seems to work correctly, if I remove this Tooltip the above warning goes away. This is a string value, I checked my data and this column all has values. With or without this Tooltip I get the same visual. I also tried filtering out blanks as a Filter.

Has anyone seen this before, is it a bug or am I doing something wrong?

Thanks,

Dan