Replying this topic I've noticed a bug that was introduced after 1.20a.
In 1.20.2, particle instances using scatter option get messed. Error message appear a lot of times:
// Error: Octane: Error getting the cached shape index of mesh: "|pCone1|pConeShape1", using the first one //
The effect is that the instances (just particles, transform instances work fine) lose the material and all the particles appear as the last index. If I switch geometry type to global, 1.20.2 can render correctly.
1.20a renders the same scene correctly also in scatter type.