I'm glad I actually found a video of it so it may not just be a random thing that happened to me since it happened to this person also. I think this might be a good DYK? if there's an explanation why this occurs since it really stinks because it can be triggered right near the end of the game and there's no way out of it.
I can't comment for certainty, but I can conject that this is likely an AI pathing problem. Once the Arwing goes to computer control, the AI performs a set maneuver, and then executes a path to fly over the entrance to Andross' domain. If the AI calculated path doesn't reach the point that it needs to within the script execution timer, it fails to move ahead in the script to where it performs the next maneuver of the somersault dive into the entrance. This is likely a scenario that never came up in beta testing as the requirements to have it execute are more than likely hard to achieve in normal play - likely beyond the bounds of what the game testers what would have achieved.