According to Bernadette Kinlaw, many people pronounce words incorrectly even though they know they’re saying them wrong. It’s just a brain thing. They can’t seem to conquer the tongue enough to say the word right.
It’s as if you’re an expert typist but your forefinger or pinkie randomly hits the wrong key. It’s similar to knowing each step of your favorite dance, but your foot decides to land in the wrong place. Or it’s that time you miss your exit off the highway even though you’ve taken that same trip hundreds of times.