Still haven't got to the bottom of the PM issue, it's literally the same membership-expired messages that have been working unchanged for probably a decade. For now, I disabled them.
Then it promptly fell over with a "memory limit exceeded" error as it choked on three days' worth of views.
I managed to get the script to run to completion; need to see whether it completes tomorrow or whether we run into issues with duplicate dates in the views tables (because, of course, I didn't get this to work until just after midnight, server time).
My friend and I applied for airline jobs in Australia, but they didn't Qantas.