One thing that is still open after julia.endo’s answer:

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

NicoleRaleigh said:

Whatever the answer turns out to be, the method for getting there is the same: state the assumption, do the arithmetic in public, and invite the…

Filing a mild objection. Mild because I might be wrong; an objection because nobody has addressed the case that does not fit. 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.

OP back with an update, since a thread like this is useless without one.

Reporting back with a partial result, because a partial result is still better than silence. Two of the three things suggested helped; I cannot separate them and I am not going to pretend otherwise.

NicoleRaleigh said:

Whatever the answer turns out to be, the method for getting there is the same: state the assumption, do the arithmetic in public, and invite the…

Thank you — that is the clearest version of this I have read, and I have read a lot of them.

Coming back to something from earlier in the thread, because it keeps being talked past:

Follow-up: I read the paper rather than the summary and the qualifier I was missing was in the second paragraph of the results.