One recommended pattern to do initialization steps of Active Objects is to postLIFO() an initial signal to self.
In QXK scheduler (QP/C 5.7.3a) this causes assert in QXK_sched() because scheduler is still locked in this phase. Calling QActive_postLifo() causes scheduling via QACTIVE_EQUEUE_SIGNAL_().
QACTIVE_POST_LIFO((QActive *) me, &ao_initial_sig);
Add following code to start of QXK_sched_()
if (QXK_attr_.lockPrio == (uint_fast8_t)(QF_MAX_ACTIVE + 1))