Okay. Thank you. I had already found the section in the manual you quoted and identified the culprit, after turning seven different scripts on and off and seeing what would happen when I created a new folder.
It’s a script called “DEVONthink-Import and Delete.” Created by Christian Grunenberg. Now that I have found it I have a vague recollection of having imported some scripts a couple of years ago in an ambitious moment when I was going to try to learn scripting. (An ambition that didn’t go far.)
But I don’t recall this particular script triggering this way when I was on Catalina and Big Sur. I upgraded to Monterey in November, and it seems that this is when the problem started.
I think I will just disable all 7 of these scripts and see what happens.
Thank you for your help. Maybe they’ll let me remove my straitjacket and release me from my padded cell.