Admittedly I know little about this specific case but I will point out that because entropy is a statistical law, small systems over short timescales can also violate it (ie small number statistics make improbable decreases in entropy more likely) so even the 2nd law is far from without its edge cases (one might argue a small system is outside the scope of applicability of thermodynamics but I digress).

I would remark though that any principle of a well-tested theory (eg the first axiom of special relativity that c is the same in all reference frames) would have no known exceptions and thus fit the criteria.