Your second paragraph seems quite insightful. I will occasionally write out the wrong word, only to re-read the incorrect word as the word I intended to write, totally missing my mistake. As you describe, I think most often it relates to the 'fuzzy matching' of the first few bits of a word, my brain auto-completes the action of selecting the wrong letters for the word as the intended word.

I seem to be able to break the spell in a number of ways. When I'm re-reading a final draft of something (say an important email) I will try to eliminate context and deliberately read each word individually. Another way to break this spell is to read a document much later in time. Sometimes the pattern matching self-corrects later, or seemingly I have forgotten the verbatim phrasing of the idea that I previously wrote, and so upon reading I pick up the mistake.

I read thousands of words per day, probably write well into the hundreds. Fortunately, the amount of errors for me is very low, but if this were to happen with increased frequency, reading and writing would be quite stressful.