Simple answer: Your brain is much faster than your hands.

Your tongue is also faster than your hands, that's why you'll never have this happen when you speak, only when you write.

Try to do this experiment: Notice what word is in your head while typing a sentence. You'll notice that the word in your head is often a couple of words further along the sentence than the one you are typing at that moment

So it's easy for your hands to skip a word sometimes. This isn't dyslexia in my opinion..