IMO the reason this happens the computer automatically substitutes word if you don't proof read it carefully it goes missed. Also I find that i sometimes (quit often) using IPad key board I sometimes miss the letter I'm trying to hit, the computer will automatically fill in word it thinks what I am trying to type.
Also sometimes my finger nail hit the letter and it don't register, good example is th "the". I did hit all the letters for "the". And again if not proof read carefully it gets caught by the grammar police. Actually IMO as long as it don't change intent what the big deal?
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