Yeah, make sure you have the approach procedure set up before you start the flight. If you add the approach to your MCDU after you already start your flight session, that’s when the flyback bug happens.
That’s why I always create a full flight plan, with Departure, Arrival, and Approach patterns setup on the world map before I even press FLY. so the entire full flight plan is loaded when you start the flight. By the time the approach phase is activated, there’s no flyback bug because the whole approach is already part of the flight plan.