I wouldn't bet their "fast" response is due to them internally already knowing, so much as the PR hit from getting to the top of the PC enthusiast forums on reddit. None of the statements so far even suggest they've reproduced anything wrong, leaving vague statements of investigating it or adding more limitations in case that was an issue.

I remember a while ago something similar happened when someone read a lot into a comment into the open source AMD GPU driver as the "Shader Prefetch" feature of their GPUs was broken and disabled. AMD ended up having to issue a statement saying it's enabled and working where it benefits performance - and that shot to the top of those same forums and people "demanded" an explanation, and that was just an internal detail of hardware performance, not even a user-visible feature. To this day some commenters think the performance is somehow hobbled by this, so there may be more pressure to get faster responses.

I personally work on GPU drivers, AMD GPU drivers, but not on windows. I actively avoid commenting on things I have personal knowledge of, so I don't accidently leak something, but also because I see so much /wrong/ stuff repeated on the internet. In fact, I would say the majority of the specifics that are "generally accepted" on those subreddits are wrong to the point of being misleading. And a couple of times I've tried to question things I knew were incorrect I was heavily downvoted and dogpiled, so I gave up.

So while I have no direct knowledge of anything related to the CPU and it's power management, I'm trying to avoid Gell-Mann amnesia on "facts" repeated in those same subreddits.

So my current position is there may be an issue here, it may even be related to the SoC voltage regulation currently being blamed, but the "evidence" so far could also be caused by a thousand other things.