@gemats
Sorry i really don’t have any idea to this strange behaviour, perhaps someone like @jonatandor35 could help out.
Could it be something with refenced fields? You mentioned it in some of your posts.
Could it be something with the type of the fields? But you already said, that “languages” is a “Text-Field” (STRING-Field) and it also do not work.
STRANGE!
By the way, could you solve your “INCLUDE-PROBLEM” ?