If they managed to turn around partially before they understood what was going on, autopilot could have continued in that direction as well. That could possibly

If they managed to turn around partially before they understood what was going on, autopilot could have continued in that direction as well. That could possibly be why they're looking at the Malacca straights now instead of the original search zone since primary radar supposedly detected the plane in that vicinity at 2:40am, an hour after it went dark.