PedsEndoPhilly said:

Worth answering the question that was asked rather than the one behind it.

Coming at PedsEndoPhilly’s question from a different direction. The honest answer is that the effect is real, the magnitude is contested, and the individual variation is larger than either. Those three things can all be true at once, and most arguments here are two people holding different parts of that.

Reporting back.

Update, and it is the boring outcome: nothing was wrong. The measurement I was reading had moved less than its own week-to-week variation, which somebody said upthread and I did not believe.