Grouping in SolrCloud fails if indexed="false" docValues="true" and stored="false"

In SolrCloud only (it works in stand-alone mode), a field defined as:
<field name="boolean_mvn_in_dvy_sn" type="boolean" multiValued="false" indexed="false" docValues="true" stored="false" />

will fail with the following error:
java.lang.NullPointerException
org.apache.solr.schema.BoolField.toExternal(BoolField.java:131)
org.apache.solr.schema.BoolField.toObject(BoolField.java:142)
org.apache.solr.schema.BoolField.toObject(BoolField.java:51)
org.apache.solr.search.grouping.endresulttransformer.GroupedEndResultTransformer.transform(GroupedEndResultTransformer.java:72)
org.apache.solr.handler.component.QueryComponent.groupedFinishStage(QueryComponent.java:830)
org.apache.solr.handler.component.QueryComponent.finishStage(QueryComponent.java:793)
org.apache.solr.handler.component.SearchHandler.handleRequestBody(SearchHandler.java:435)
org.apache.solr.handler.RequestHandlerBase.handleRequest(RequestHandlerBase.java:173)
.
.

curiously enough it succeeds with a field identically defined except for stored="true"