If the field filter condition is set to show a single field value, set the OlapFilterUsingWhereClause property to SingleValuesOnly.
Subselect clauses cannot be used in MDX queries containing calculated members, with the CurrentMember function used in the expression. In such instances, set the OlapFilterUsingWhereClause property to Always.
To learn more, see the OLAP Filtering Specifics section in the Filtering Basics topic.