I you try to add knut calendar, then click on cancel you will find that new process named akonadi_knut_resource is still running even if you close KOrganizer or restart akonadi server.
Another weird behavior is that after cancelling the creation of any kind of calendar (not only knut) there will changes in akonadi "~/.config/akonadi/agentsrc" file : 
in [InstanceCounters] region the counter of cancelled calendar increases even if creation process was cancelled, and in [Instances] region a new line that corresponds to the cancelled calendar will be added.