Everything looks good.
Can you share the scikit-learn version?
I was facing a couple of issues with
scikit-learn==0.19.2 and check if that helps.
Also please note that this discussion was for Botpress 10.x, where as you are using 11.x. I am not sure what has changed between these two.
I would suggest using botpress 10.x as Botpress Server (v11) currently in public beta and is not recommended for production usage just yet.