It’s just a subjective observation.

It just can’t be a case simply because how ML works. In short, the more diverse and high quality texts with reasoning reach examples were in the training set, the better model performs on a given language.

So unless Spanish subset had much more quality-dense examples, to make up for volume, there is no way the quality of reasoning in Spanish is on par with English.

I apologise for the rambling explanation, I sure someone with ML expertise here can it explain it better.