Arahants continue to learn from their mistakes. They don’t get knocked off course by them because they have no conceit that’s going to be challenged by the mistake, destroyed by the mistake, or feel threatened by the mistake.
"Even arahants make mistakes. Their virtues in terms of the basics of a virtuous life — the five precepts — are unshakeable. They don’t make those mistakes any more, but simple mistakes in saying the wrong thing to the wrong person: That’s human. It has nothing to do with defilements of the mind. It’s simply the fact that we’re human beings with limitations. What’s different about arahants is that they continue to learn from their mistakes. They don’t get knocked off course by them because they have no conceit that’s going to be challenged by the mistake, destroyed by the mistake, or feel threatened by the mistake." ~ Thanissaro Bhikkhu "The Path of Mistakes" (Meditations4)