There is this answer from Brandon that goes against the theory of Cultivation helping. It might be that Honor made himself vulnerable to Odium by breaking some agreement. They've made it pretty clear that they can break oaths, but there are consequences. I don't know much about Autonomy, but there's something to Cultivation grooming new shard vessels. That should be consistent with the shard's intent, and Rayse was not a man in control.
I'm thinking more along the lines of, while Honor and Cultivation were allied against Odium, when Tanavast started breaking down towards the end of his life, it would be consistent for Cultivation to assist with a mercy killing. It's admittedly a stretch since we know Odium is responsible for the bulk of it, but there's still a lot of unknowns.
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I definitely did not forget to put the 2020 GOTD Guru winner, azuarc in my sig!