sameAs vs. differentFrom

I was surprised to see that two individuals that were previously asserted
as owl:differentFrom were inferred to be, at the same time, owl:sameAs (due
to some unrelated axioms). Are these two properties not supposed to be
disjoint? Do reasoners know they are disjoint? I certainly have *not *seen
these two explicitly declared as disjoint, but I thought that that was
something that goes without saying. (And if they have not been conceived as
disjoint, why so?)

Anyway, what struck me was that the reasoner did not deem the ontology
inconsistent.

Any W3C OWL insiders care to explain this?

Many thanks,

Christian

-- 
"People think that I must be a very strange person. This is not correct. I
have the heart of a small boy. It is in a glass jar on my desk." -- Stephen
King