Hey Sacha, do you have seam faces in your application
I removed seam faces because I got a very strange error about transactions (Nested transaction not supported) while persisting my objects to the database. It all worked again after removing seam faces. So I forgot about the error.
Now I added seam faces and the status message works fine :-) Thanks for the help.
Anyway... now I have the transactions error again :-( I will have a look on that in the next days.