Note how the original incipit of Marcion, according to Wautier (in this influenced clearly by Georges Ory) has Jesus descended in the
Sheol (
=="Capernaum"), freeing the souls there:
The fifteenth year of Tiberius' principate,
Christ, descended from Heaven, appeared in Capernaum.
Having taken on the appearance of a man, he
appeared 30 years old.
Cain and those who were with him ran to him
the sodomites, the Egyptians and others, all
others, all those who had been guilty of
indignities and Christ saved them.
All were struck by his teaching~,
because his word had power
But a demon called out to him:
"What have you to do with us, Jesus? You
have come to lose us".
I know who you are: the Holy One of God.
Christ rebuked him:
- "Get behind me, Satan".
Only after, the Marcionite Jesus
ascended from Sheol (==Capernaum) to Bethsaida, and from there he addresses human people, not only demons:
Ascended to Bethsaida
Christ did not preach anything new there.
Then, people opposed him the saying:
Physician, heal yourself
This explains why the demons know already him (Jesus had already preached explicitly his new message in the Sheol) while he is more implicit on the earth.