Huh, that's odd. BTW you can use 'set flipped' to avoid needing another animation frame. I'll look in to this, but in the mean time a good workaround is probably to use an invisible object which does not animate or rotate with the physics behavior, and every tick position the visible Ship on top of that. I think it's to do with the rotation of the Physics object, so if the invisible object does not rotate it should be OK.