This may be helpful from the documentation (Persistent Revokes):
The list of revoked tasks is in-memory so if all workers restart the list of revoked ids will also vanish. If you want to preserve this list between restarts you need to specify a file for these to be stored in by using the –statedb argument to celery worker:
$ celery -A proj worker -l info --statedb=/var/run/celery/worker.state