To me, it says nothing more than Channa passed away without attachment (upādiyati).
upādiyati
to take hold of, to grasp, cling to, show attachment (to the world), cp. upādāna
Surely, a stream-enterer can pass away without attachment; even though the underlying tendencies of the stream-enterer are not yet uprooted. SN 22.22 has a similar teaching:
“The five aggregates are indeed burdens,
“Bhārā have pañcakkhandhā,
and the person is the bearer of the burden.
bhārahāro ca puggalo;
Picking up the burden is suffering in the world,
Bhārādānaṁ dukhaṁ loke,
and putting the burden down is happiness.
bhāranikkhepanaṁ sukhaṁ.When the heavy burden is put down
Nikkhipitvā garuṁ bhāraṁ,
without picking up another,
aññaṁ bhāraṁ anādiya;SN 22.22
anādiyanta
negative adjective
- takes, accepts, receives; takes up, undertakes; appropriates; seizes, grasps
Note: the word “kaya” does not literally mean “physical body” or “rupa”. I recall there was a topic about this, here: 'Kāya' and 'body' in context. It seems a ‘kaya’ can be any ‘group’ of aggregates, including mere mental ideas. Thus, when SN 35.87 says Channa did not attach to another ‘kaya’, it could simply mean Channa pass away without wishing for rebirth in heaven or some other type of mental attachment. Personally, I don’t read the sutta saying the Buddha said Channa was not ‘reincarnated’ into a new physical body again. But I could be wrong. 