LindaRN_retired said:

Almost every unanswerable question in these threads is unanswerable because three things changed in the same fortnight, and no amount of subsequent…

There is a second half to this that has not been said yet. It helps to say which part of this you are uncertain about. A precise question gets a precise answer; a general one gets everybody’s favourite anecdote.

Adding the numbers, since they settle part of this. Say what you would expect to see if you were wrong, before you look. It is a small discipline and it changes what you notice.

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

How would you tell the difference between that and the alternative explanation?

jason_paloalto said:

Say what you would expect to see if you were wrong, before you look.

Pushing back on jason_paloalto here. Pushing back on the anecdote-stacking. Twenty people reporting the same thing is twenty samples from the same self-selected pool, not twenty independent confirmations.

Closing the loop on my own question.

Closing the loop. The answer turned out to depend on the detail I had left out of the opening post, which is a lesson about how to ask rather than about the subject.