When executing /etc/init.d/ttn-pkt-forwarder stop, the process /opt/lora/mp_pkt_fwd usually does not also get stopped.
This breaks functionality with packages like monit, which attempt to restart the service when an issue is detected. Instead, a duplicate process is spawned, and the problem continues.
I fixed this issue by modifying the /etc/init.d/ttn-pkt-forwarder file, so that do_stop() does killall mp_pkt_fwd. The original behaviour is killall -1 mp_pkt_fwd. This is a "quick fix" but the issue lies in mp_pkt_fwd refusing to exit cleanly.