Addition of /bin sync on its own line after line 1221 appears to fix the fifo problem.
The process would always choke is run from the command line. The run during the cron job would usually run correctly, assumingly as the machine was under heavier load. Also observed that the crashing was more likely with increasing 'capacity' of the server hardware. Devuan 1.0 Jessie. Dual Core E8400 @ 3.00GHz awk -> mawk apt-move 4.2.27-3 -- M