I booked an award flight. CMH-JFK-CDG. Picked a specific itinerary for the sake of lounge time. I have received a few notification that my itinerary changed. They keep moving my CMH-JFK flight to the option with the least connection time, but the original flight still exists. I call them, they fix it, then a month or so later it happens again. The best I can tell every time there is even the smallest change in departure time something in the system automatically rebooks to what it thinks is the best.

Anyone have any idea why this is happening and anything i can do to prevent it?