Major Description
DocValues aren’t really supported in poly-fields at this point, but they don’t complain if the schema definition of the subfield has docValues=true. This leaves the index in an inconsistent state, since the SchemaField has docValues=true but there are no DV for the field.
Since this breaks compatibility, I think we should just emit a warning unless the subfield is an instance of PointField. With [Int/Long/Float/Double/Date]PointField subfields, this is particularly important, since they use IndexOrDocValuesQuery, that would return incorrect results.