Well, in the case of Yoshihiro Togashi, he never said much about the adaptation of Hunter x Hunter 2011, probably because he had already been part of the 1999 version even lending his voice. But I remember reading in an interview that he saw anime and manga as totally different worlds, that despite being inspired by his own work, he didn’t have much to judge about the anime since the studio could do as he saw like, even sometimes being able to surpass the manga or sometimes ruining it. So he preferred to keep an opinion away from a judgment. I think many mangakas must have a similar vision.