I have a projet with only FR as available language

When resources are indexed, the full field is indexed in all available languages. So in my case, only 'full_fr'

When searching on documents, no language is specified (language is null). By default, the FullTextQuery will search on default language which "en" => full_en

So no documents are found

q=(full_en:(test))&start=0&rows=2147483647&fl=id,score&fq=_documentType:projectResource

First fix will be to specified the language search according the current sitemap language

Second fix will be to set a language of indexation as a project configuration parameter :INTRANET-211