That is not a true assessment; the code is stored in a Git repo. I tried to wind it back, but the original version also fails in the same way, so there must be something else going on. In any case, for the record there were two changes made: Both involved adding more debugging info here (I elided it in my post, but it was basically changing the log line from "Error when running [$external_command]" to "Error when running [$external_command] for object id [$object_id]", for both error lines). It's also possible that the Perl version on the server was updated, but I can't recover that info now; if so, it was likely from 5.16 to 5.24. But I also tried running it under 5.16 and got the same results.

Line 459 was the "$child_output = capture($external_command);" line in the code I posted.