Traceback shown in log even when using custom exception handler

Task:

def f():
    raise Exception("I should not see this!")

I run the worker with rq worker --url=redis://redis:6379 --with-scheduler --name=worker1 --exception-handler=app.my_exception_handler -d and when I enqueue and run f() my custom exception handler is invoked, but I still see f's traceback in the log. Is this expected?