I am not an expert, but I do understand the distinction that is being made here. It makes sense to describe the result of pre-training as a ‘next token’ predictor as that’s what it’s been trained to do, not because it’s an autoregressive architecture that produces tokens one at a time.
If this base is then trained using RL towards a different objective (maths and coding), the model becomes fundamentally a different thing and the recent models are clear evidence of that, regardless of they fact they remain autoregressive.
Does the architecture change or the weight change?
If you modify an engine to increase it’s output by adding sensors and an ECU, you don’t change the fact that is powered by gas.
If you use RL to increase the accuracy, it’s still a next token prediction, just more accurate.