I'm surprised a pro like Randy drove the comp in full auto, and then complained about it not always being in the right gear. If that happens to any driver in any car on any track, the first thing you would do is switch it to manual and take control, specially if that's affecting track times
Out of several autos I've driven (spirited driving, not track) I feel BMW's transmissions communicate well with the driver and hold gear when necessary and quickly learn what the driver wants to do. But of course they'll never be as good as the driver selecting the right gear.
That's a fantastic video by the way!