Yes, & in a basic sense it (with God's related crosslike acts)
is the _only_ scandal we ought to allow. It is "foolishness to the
Greeks". But I'm not sure irrational is the right term. The cross
makes no sense if you start with prior assumptions about God & then try
to make the cross fit. What we have to do is _start_ from the cross &
the belief that there God is revealed.
As far as construction of a logical system is concerned, a
postulate or axiom - as long as it doesn't contradict another postulate
or axiom - can be freely chosen. It can't be irrational. The criterion
of coherence with observation comes in when you try to use the system
as a map of the real world - the difference between pure math & physics.
In theology, the familiar dissonance of "How could an omnipotent &
beneficent God let __________ happen?" shows that common-sense theology
doesn't really work so well. The theology of the cross sounds more
bizarre, but it's consistent with reality.