Ok I found it. Last year I modified my music structure by creating a custom tag with MP3Tag.exe. The new Tag name is Mediatype (Studio, Live, Compilation, Single etc...)
My Library is organize like this: Album Artist (grouped)/Album Artist/Mediatype (custom MP3Tag)/Album/Sample Rate.
To correct all the UNASSIGNED DSF DSD songs, I have to update the tag Mediatype for all the DSF file within the jriver via the TAG option even if the tags are already correct using MP3Tag editor. There is something that jriver cannot read in the .DSF with this custom tag (Mediatype) created from MP3tag.
My others files tagged by MP3Tag using the same method (FLAC, ALAC etc... ) are ok. JRiver can read it during the import and i dont have to update it with JRiver TAG engine.
I don't know if someone else is have a similar situation with a gap between MP3Tag and JRiver ?