This effectively eliminates the use of query layers in the new version of operations dashboard. If you try to create a category filter for instance, it executes a statistics query before retrieving distinct values!
outStatistics on a query layer is supported in 10.3.1.
pls see 'New in 10.3.1' section in ArcGIS REST API - Map Server Layer Resources help topic.
if it does not work for some reason, pls contact Esri Support and it can be looked at.