One thing that is still open after paige_pharma’s answer:

What did you change at the same time, and can you separate the two now?

Reporting back.

Late follow-up. I did not do what was suggested, I did something adjacent, and it worked; posting the difference in case it matters to somebody.

hank_denver said:

Keep the original post as written when you update it, and add the correction underneath.

That is right, and it stops being right at the edges. The general case is well behaved; the interesting cases in this thread are all at the boundary where the general case breaks.

hank_denver said:

Keep the original post as written when you update it, and add the correction underneath.

Bookmarking. The distinction being drawn above is the one nobody else makes. Taking it to my next appointment.

Adding the clinical framing, because it changes how the question reads. The mechanism and the magnitude are separate questions. Agreeing that something happens says nothing about whether it happens enough to act on.

Correct me if the detail matters more than I have assumed.