Segfault on OwnThread Operation on a Component with no Activity

In my project if I created a composant named "OperationOwner" which has an
OwnThread Operation named "op". But I forgot to give him an Activity. When I
call "OperationOwner.op" in the TaskBrowser I get a segfault. Do I forgot to
write something in my Operation "op" C++ code ? Or is it a abnormal Orocos
behavior ?

When I change OwnThread to ClientThread I no more have the problem (so the
code in "op" is OK and is simple anyway (just a printf))
When I add an Activity to OperationOwner I no more have the problem (so lack
of Activity seems to be the problem)