This is still happening. I think there was a task for it already that got solved (T647). However, due to T87135 this still happens quite frequently.
E.g. T104164 was created June 29th. And July 12th a change was made to the CC-list (the first change to that task) . That change resulted in an IRC notification. Presumably because the CC-filter didn't work as the event also also contained a "set Security to None." component.