group.sort broken, can through AIOOBE if clause length differs from sort param, or cast exception if datatypes are incompatible with sort clause types

"params":{
      "q":"*:*",
      "group.sort":"priceAmount asc,rnd desc",
      "indent":"on",
      "fl":"priceAmount,flightTripId,brand,slob,cabinType,tripDuration",
      "group.limit":"100",
      "fq":["searchId:e31a0c58-9056-4297-8d70-049017ba4906",
        "doctype:offer",
        "flightTripId:(DY6020421-SK2360519 OR DY6020421-SK2600519 OR DY6020421-SK2620519 OR DY6020421-SK2740519 OR DY6020421-SK2900519 OR DY6020421-SK2860519 OR DY6040421-SK2380519 OR DY6040421-SK2440519 OR DY6040421-SK2480519 OR DY6040421-SK2520519 OR DY6040421-SK2600519 OR DY6040421-SK2620519 OR DY6040421-SK2720519 OR DY6040421-SK2740519 OR DY6040421-SK2800519 OR DY6040421-SK2840519 OR DY6040421-SK2820519 OR DY6060421-SK2480519 OR DY6060421-SK2740519 OR DY6060421-SK2800519 OR DY6060421-SK2840519 OR DY6060421-SK2900519 OR DY6060421-SK2860519 OR DY6060421-SK2820519 OR DY6080421-SK2440519)",
        "maximumLegDuration:[* TO 180]",
        "departureAirportLeg1:(OSL)",
        "(arrivalAirportLeg2:(OSL) OR (* NOT arrivalAirportLeg2:*))",
        "arrivalAirportLeg1:(BGO)",
        "(departureAirportLeg2:(BGO) OR (* NOT departureAirportLeg2:*))"],
      "group.ngroups":"true",
      "wt":"json",
      "group.field":"flightTripId",
      "group":"true"}}

ERROR [20160404T104846,333] qtp315138752-3037 org.apache.solr.servlet.HttpSolrCall - null:java.lang.ArrayIndexOutOfBoundsException: 1
        at org.apache.solr.search.grouping.distributed.shardresultserializer.TopGroupsResultTransformer.transformToNativeShardDoc(TopGroupsResultTransformer.java:175)
        at org.apache.solr.search.grouping.distributed.shardresultserializer.TopGroupsResultTransformer.transformToNative(TopGroupsResultTransformer.java:137)
        at org.apache.solr.search.grouping.distributed.responseprocessor.TopGroupsShardResponseProcessor.process(TopGroupsShardResponseProcessor.java:129)
        at org.apache.solr.handler.component.QueryComponent.handleGroupedResponses(QueryComponent.java:750)
        at org.apache.solr.handler.component.QueryComponent.handleResponses(QueryComponent.java:733)
        at org.apache.solr.handler.component.SearchHandler.handleRequestBody(SearchHandler.java:405)
        at org.apache.solr.handler.RequestHandlerBase.handleRequest(RequestHandlerBase.java:155)
        at org.apache.solr.core.SolrCore.execute(SolrCore.java:2082)

  protected ScoreDoc[] transformToNativeShardDoc(List<NamedList<Object>> documents, Sort groupSort, String shard,
                                                 IndexSchema schema) {
    [...]
    for (NamedList<Object> document : documents) {
      [...]
      Object sortValuesVal = document.get("sortValues");
      if (sortValuesVal != null) {
        sortValues = ((List) sortValuesVal).toArray();
        for (int k = 0; k < sortValues.length; k++) {
          SchemaField field = groupSort.getSort()[k].getField() != null
              ? schema.getFieldOrNull(groupSort.getSort()[k].getField()) : null;