Hi, in the init script, ICINGA2_RUN_DIR is incorrectly defined as /run/icinga2 instead of /var/run/icinga2 (which is what is set by the ebuild during compilation). As a result, icinga2 can not be started with the init script. Prepending /var to the variable fixes the issue as expected.
It seems that this is simply caused by /var/run not being a symlink to /run on my system because it had not been rebooted in over a year.