Dyslexic here. Dyslexia is not a single condition. The only way we define dyslexia is difficulty reading caused by the way the brain processes text so not something like poor eyesight or low intelligence. Therefore by definition this is not what a large percentage of dyslexics experience because there is no common experience. Maybe this is how some dyslexics experience reading, but I am not one of them and I don't think I have ever actually heard another dyslexic describe literally seeing letters changing as they look at them. It is often more that things seem to change when you aren't looking.
For me personally, I have no problem with letters. A "b" is never a "d" or whatever stereotypical explanations you might hear about dyslexia. My problem is with entire words. I will often substitute one word for another while reading (and writing). I can go back and might still read that incorrect word. But I don't think I ever really "see" that incorrect word. It is more that my brain is lazy and isn't actually reading, it is just assuming what is supposed to be there and that assumption is occasionally wrong.
For me personally, I have no problem with letters. A "b" is never a "d" or whatever stereotypical explanations you might hear about dyslexia. My problem is with entire words. I will often substitute one word for another while reading (and writing). I can go back and might still read that incorrect word. But I don't think I ever really "see" that incorrect word. It is more that my brain is lazy and isn't actually reading, it is just assuming what is supposed to be there and that assumption is occasionally wrong.