Ah, I got it, /var/log/ff/faxfinder reports:
Nov 28 08:32:34 swog-ff FaxScheduler: (load_fe:525) rcpt_fax contains invalid character: john doe (censored)
It turns out that one of our clients occasionally put a person’s name in as a fax number. Please consider this thread solved, thank you.
Excellent! Your recommendations have been accommodated for in our script. The system is up and running 100%.
Also, is it possible to embed the extension, the line number, etc. into the PDF metadata?