BINGO! Quite surprised that this should have changed on a minor, late OS revision, but there we are.
Interestingly, I don't have that on my other Mac, running the newest OS. But there we are.
Thanks, all.
I'm on Apple Silicon, not Intel. (And I'm on OS 15.8, which is two versions below the recently released OS 27.)
And I'm using the ARM build.
I have re-downloaded the app (in the unlikely event that the binary somehow got damaged in such a way that it still runs), and deleted the Cache folder. Are there are parameters or settings I can use in the config file that might be useful?