This appears to be working correctly in the game..
It really isn't. The correct thrusters do indeed fire, but the ship slants in the wrong direction. Here's a screenshot of me rolling left. As you can clearly see, the ship is at a diagonal going from top left to lower right. If the right thruster is pushing up and the left thruster is pushing down, the diagonal should be reversed, going from lower left to top right. I hope this makes sense.
http://imgur.com/a/zDK0M