Public Notification App: Unable to Export Attribute Expressions in CSV format?

[sophie-aubry]

Will the public notification app allow custom attribute expressions to be exported in a csv? 

I created an attribute expression which returns a value representing the acreage of intersection between two layers in my map (floodway that intersects with land parcels). In my web map, I customized the parcel layer's pop-up to include this attribute expression.

I brought this map to the public notification template but when I select one of the parcels and go to export the information that should be calculated by the expression it just keeps spinning. Is it unable to export custom attribute expressions? Can it only export already created fields in the layer's attribute table?