Hermione Granger
Hermione will experience, what at first will seem like, false memories. She will begin to remember things that didn't happen (or rather, they happened in canon!verse) and forget things that did (but not in canon!verse). These will not be permanent memories or lack thereof, but rather lapses. It won't make a great deal of sense to her until she starts writing them down and organising them in a chronological order.