A query is based on eFashion universe and returns two objects: measure [Promotion Cost USD] and dimension [Duration].
The variable [Cost] is defined as
=If [Duration]>0 Then [Promotion Cost USD]/[Duration]
The following formula in report’s cell returns #MULTIVALUE
=Sum([Cost])
If I just replace the variable with the expression, it will return correct value
=Sum(If [Duration]>0 Then [Promotion Cost USD]/[Duration])
The following formula also returns correct value
=Sum([Cost] ForEach([Duration]))