Lumira: GetData fails on hierarchy-aggregated measures

I have a measure with a Dimension with an hierarchy.The higher-level-values are aggregated along that hierarchy. All data on all levels is displayed fine in a crosstab. Now I want to read the values via getData. This works fine on the lowest hierarchy-level but fails for all aggregated values (Error: "No matching data found in selection" and "Could not find member"). How can I get the aggregated values? Lumira version is 2.2 SP0 Patch 3 (Version: 22.0.3).