The Breakdown
The notice went up at 4:07 PM on a Friday. That timing is not an accident and it is not a conspiracy either. It is standard practice, well documented, used by administrations of both parties, because the news cycle thins out over a weekend and by Monday the story is three days old.
The change itself adjusts an eligibility threshold. If you are already enrolled, nothing happens to you immediately. If you are applying after the effective date, the paperwork requirement is different and the processing window is longer.
Rough estimate on who this touches: about 400,000 people, concentrated in the group least likely to be reading federal register notices on a Friday evening.
There is a public comment period. It is open now and it closes sooner than these usually do.