The pipeline module was supposed to terminate whenever it saw something that isa('Pipeline::Production') come back from a segment. Of course in the released version it wasn't doing that.
Oops.
Ah well, bug fixed, problem solved.
Other than that, I'd like to say thankyou to everyone who dropped me various messages of sympathy about the last journal entry. I really appreciate it. In retrospect I probably shouldn't have posted what I did, but it was a reactionary entry, and I don't regret it.