unsurprisingly, higher poly count (815 faces per one fillet) helps to neutralize artifacts.
this is the close up of the default obj inside max:
https://imgur.com/a/dJUXqE9
Forgive me but its a bad topology, I see a lot of room for improvement (getting rid of perpendicular triangles (in blue) could be a good starting point (plasticity's default example proves its doable)
P.S. Here's a promo of some max plugin which bridges edges with non-equal segment number without perpendicular triangles:
https://www.youtube.com/watch?v=DzBid27gDRM