I don't think you are lying. I think that there are always exceptions to the rule, abnormality, deviancy... Whatever you want to call it. It does happen and just because it is rare does not mean it did not happen.
However, it is just that: a rare occurrence. If it happened with almost every coral snake, or cotton mouth, in every encounter, then you definitely have across something extraordinary. Generalizing how something as a whole must behave based on 1 or 2 or even 3 encounters...