" Looks like when using the json facet api, SimpleFacets is not used, replaced by FacetFieldPorcessorByArrayUIF "
That is expected, I remember Yonik to stress the fact that it is a completely different approach to faceting ( and different components and classes are involved). But your first case, it may be worth an investigation. If you have the tools and you are used to it I would encourage you to reproduce the issue and remote debug it from a Solr server. Putting a breakpoint in the Simple Facets method you should be able to solve the mystery ( a bug maybe ? I am very curious about it. ) Cheers ----- --------------- Alessandro Benedetti Search Consultant, R&D Software Engineer, Director Sease Ltd. - www.sease.io -- Sent from: http://lucene.472066.n3.nabble.com/Solr-User-f472068.html