Hi Renaud,

First and foremost, thanks for the bug report and for the very explicit test case!

We are currently investigating the cause, but it's definitely a bug on our side.

Status: we tracked the problem down to the way we use SortedDocValuesField. This type of field, on contrary to classic fields, do not get automatically analyzed by Lucene when processed in org.apache.lucene.index.DefaultIndexingChain.processField(IndexableField, long, int).
I'll try to find how exactly to use SortedDocValuesField properly. I'll come back to you when I have more information.