A restart of systemd-journald on irc.wikimedia.org caused ircecho.service to sound out further updates (https://phabricator.wikimedia.org/T216607#4968319).
While it was broken the Icinga status for kraz was all fine, the "ircecho bot process" only checks whether the udpmixecho.py process is present.
I'm not 100% sure how to best improve the check to make it detect such an error, if there are logs it could be checked whether there was any update within the last 10 seconds or so. Or given that there are channels which are very busy, the check could also join a specific channel and warn if there was no actitivity over 5-10 seconds or so.