In Malnik's few interviews, I didn't hear any mention of a falling out. I was, however, very bothered by Malnik releasing pictures of the children. Why release pictures of Michael's children after Michael died? It's not like the children died. It makes no sense to release the pictures when their father did not want the kids to be in the spotlight.
But I do have the same question about John Landis (the director of Thriller and Black or White). What happened between Landis and Michael? On the Black or White set, they seemed very friendly (remember the Mac and Michael food fight? That's the one), but early this year, Landis sued Michael and he made some critical remarks about Michael after Michael's death.