This week a curious controversy showed up in the open LLM world: Rio 3.5 Open 397B, presented by the City of Rio / IplanRIO in the Rio 3 Open announcement as an open model.

The accusation: in practice, the published checkpoint, meaning the model weights file, was a direct blend of Nex-N2-Pro and Qwen3.5-397B-A17B, without initial credit to Nex.