Bumped into this one on production... 
We had a table with a column that was so close to zero as to be irrelevant, and the Perspective table just shows NaN...
Paste this into a table's data property and you get it right away:
[ { "TinyValue": 7.496146992025388e-8 } ]
If I change the numberFormat setting for the TinyValue column to "none" or "scientific" it will start working but display excessive detail. I really just want it to show a "0" or "0.00".
This also happens using a dataset for the data property, so I suspect it is not source datatype dependent.
Why can't the standard "number" formatter handle this and just show a value near 0?