Ah, thanks for the possible clue, ratscloset. It appears this is rather a one-off problem.

But you've prompted me to recall that the product I'm testing is in its own new Runtime. That gives me a few things to try out before I report it to SM, including the collect data script. Never used that before!

I'll be back...

"If I were a shadow, I know I wouldn't like to be half of what I should be."
Mr Otsuka, the old black tomcat in Kafka on the Shore (Haruki Murakami)