Hi there,
I have got the same issue in my NAS (running 3.0.76 with backport 4.9.18-1~bpo8+1 (2017-04-10) x86_64)
And no matter is /etc/logrotate.d/openmediavault-proftpd_xferlog exist or not.
Воеу anybody know to fix this minor issue?
Thanks for your attention. Peace!