To the contrary (as usual), Appendix II of Dune says that Navachristianity is of Chusuk.
Before the coming of Muad'Dib, the Fremen of Arrakis practiced a religion
whose roots in the Maometh Saari are there for any scholar to see. Many have
traced the extensive borrowings from other religions. The most common example is
the Hymn to Water, a direct copy from the Orange Catholic Liturgical Manual,
calling for rain clouds which Arrakis had never seen. But there are more
profound points of accord between the Kitab al-Ibar of the Fremen and the
teachings of Bible, Ilm, and Fiqh.
Any comparison of the religious beliefs dominant in the Imperium up to the
time of Muad'Dib must start with the major forces which shaped those beliefs:
4. The so-called Ancient Teachings -- including those preserved by the
Zensunni Wanderers from the first, second, and third Islamic movements; the
Navachristianity of Chusuk, the Buddislamic Variants of the types dominant at
Lankiveil and Sikun, the Blend Books of the Mahayana Lankavatara, the Zen
Hekiganshu of III Delta Pavonis, the Tawrah and Talmudic Zabur surviving on
Salusa Secundus, the pervasive Obeah Ritual, the Muadh Quran with its pure Ilm
and Fiqh preserved among the pundi rice farmers of Caladan, the Hindu
outcroppings found all through the universe in little pockets of insulated
pyons, and finally, the Butlerian Jihad.
~Appendix II: The Religion of Dune
Paul of Dune was so bad it gave me a seizure that dislocated both of my shoulders and prolapsed my anus.~Pink Snowman