Yes I did make a mistake and worse still I would have never caught it myself, being dyslexic I often miss and make obvious errors. One of the greatest changes in my lifetime was invention of spell check and cheap inexpensive computers, without both I could have never made it through college.
I have great respect for those of you who master and use the written English language without regular and constant mistakes. It is a obvious sign of intelligence—I so wish I could write better.
Lucky you. You don't make mistakes spellcheckers can't pick up. I can skip one or even two words at a time (following Murphy's law, the word I tend to skip the most is "not", even in its contracted form "n't"), or repeat words, or even do some very strange things if I get distracted (like that time I wrote my technical drawing teacher's name as "Spiral" because both words start with the same three letters and it was homework about spirals).