"killall --signal SIGUSR1 opendmarc" seem not to reliable reload a IgnoreHost file under all circumstances.
I use to run opendmarc supervised an have set "Background no" in the configuration file.
Guess: a reload is implicit done by forking a new child process but forking is just disabled
But I may be wrong.
Further investigations ...
info: I still do simply restart opendmarc to reload a new ignoreHost file
Will look into this after 1.3.2 ships.
This still remains as an issue, at least in RHEL7 (1.3.2-1.el7).
Verified by tracing opendmarc and sending USR1 signal. No action was taken. HUP signal caused it to terminate.
Workaround: must restart opendmarc