Yes, the standard and expected behavior is that logical_op(NaN, anything) == false [except inequality] because NaN is not ordered with, or equal to, anything, i

Yes, the standard and expected behavior is that logical_op(NaN, anything) == false [except inequality] because NaN is not ordered with, or equal to, anything, including another NaN. Otherwise you may have the strange behavior that two erroneous values are equal, e.g., 0*inf == tan(inf).