I wish I remembered where I read it so I could attribute it, but I saw someone describe Trump not as a liar but as a bullshitter. It's not that he lies. It's that he has no regard, one way or another, for whether what he is saying is a lie or not. He simply has a thought and recites it. It's so effortless for him to lie because, from his perspective, it's the same as telling the truth. If this is true, the pattern you've identified could be merely chance based on the probability that any random thought a person has is more likely to be wrong than right when they are incapable of learning new information.

I didn't feel like I was doing it justice, so I found the sauce...from fucking 2015. https://newrepublic.com/article/124803/donald-trump-not-liar