> 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.

It's not just your brain. It's how vision works in general. Everyone has physical blind spot (where the optic nerve attackhes to the retina) but no one can see it except if they carefully hunt hor it. Everyone can see high resolution only in a tiny area at the center of the visual field, and imagines the rest.

With dyslexia (and various physical vision problems), you're collecting even less input (due to misprocessing at some "lower layers"), so your higher-level recognition/comprehension brain has to fill in more missing deails, and so has a higher error rate.