Sorry, you are correct - I modified my original post. I get frustrated every time there's a model release and 1 week later everyone is saying NERF! NERF! 99.9% of the time these people are wrong, but you are right that it's technically not 100% due to a few edge cases.
I am more skeptical about the compute provider claim - do you have any evidence of that?
I've seen that looping and glitching behaviour in over-quantized (~Q4 or lower) local models like Llama and Qwen 3.x. Thus, it is likely that they quantize the model after release to save on compute costs (while giving a favourable result at launch). That quantization can result in changes to the model's behaviour (you are changing the weights) that could be interpreted as nerfing.
I am more skeptical about the compute provider claim - do you have any evidence of that?