Torvus Grove Double Pirates Crash
It is uncertain what causes this to happen, but it may be a side effect of getting gravity boost and/or grapple before boost ball.
When entering Torvus Grove, sometimes two "locked door" Pirate fights can occur in a row. If this happens, there is a chance that your game will crash when you move into the next room.
If the crash occurs, simply load up from your last save and you can apparantly proceed normally.
If the crash does not occur then you can proceed normally without having to worry about it happening again.