Custom Function in Pivot Table Chart not showing results


I’m doing a basic sum(Margin)/sum(Revenue) custom function column in a pivot table chart and I’m getting an empty table. Is there any condition I’m missing on why I’m getting empty values?

UPDATE: This seems to be happening only for columns created after importing the data, no function works on them and output empty values. Regular inclusion as columns does work properly outside the custom function. Original columns sum and divide properly. All columns are numeric data type.