Thank you very much for your fast response! Digging a little in the source code, I find out which was my mistake. I haven't put anything in the output_uri parameter so I was using my local laptop as output route for saving the model. I guess that because I'm overriding the old model when I do the joblib serialization, the comparison between weights will be always "equal". Maybe this comparation should be before? Anyway It's caused because I have used always the same output path in local...