JP, the way I read that RWTS paragraph is that they were not convinced the aircraft was safe, a relatively small step short of saying it was unsafe. They had questions about a number of FADEC issues that they did not understand and were not willing to endorse the aircraft until they received a satisfactory answer. This stance seems to be entirely reasonable to me and, if ignored, someone in a position of power accepted an extraordinary level of personal risk.
I agree that if RWTS stand by that statement and no changes have been made to the aircraft, then it is still not airworthy. Furthermore, if one were to apply civilian standards, the aircraft would never be airworthy unless a back-to-birth process were properly followed.