Anyone having issue where autocorrect changes when to she? It happens alot on mine.
Not here. Never happened with my L1020 and my L535 Dual SIM.
Is this problem persistent? Does this occur for other words? Short words and/or long words?
If you're using the swipe to type feature, make sure that your fingers swipe over the correct letters (not just near the letters) and all of the letters in the word you're typing for best results. I'm suspecting the big screen is getting in the way of finger movement, making gestures for short words less accurate - possibly more of a fault of the obstructed movement of the fingers rather than of the phone.
If you're typing using the regular method of tapping on the individual keys, I can't think of a reason why your phone would correct a correctly-spelled "when" to "she".
BTW, Welcome to Windows Central!