If a native speaker makes an utterance that they don't consider to have a mistake, and that other speakers of the dialect would accept as correct, then I think

If a native speaker makes an utterance that they don't consider to have a mistake, and that other speakers of the dialect would accept as correct, then I think it's hard to say that it's wrong, even if it deviates from another dialect (and even if the dialect it deviates from is the one considered the "standard" form of the language). Even taking it in a more linguistic prescriptivist direction though, those words did often have more than one accepted pronunciation listed in various dictionaries.