I have to confirm the problem. It seems to be caused by relatively small numerical errors.
I can provide an example code (game, Rubik's Cube, unfortunatelly with polish comments only). TweenMax is used to rotate PaperVision objects, I'm using only
tweens like
if (!rotating) TweenMax.to(wall, 0.8, { shortRotation: { rotationZ:"+90" }, onComplete:setRotatingFalse, immediateRender:true } );
If I'll write in onComplete code that runs another rotation (to make infinite loop), then after some rotations (slower computer, fewer rotations) rotationZ will be something like "89.97".
[Accually it could be a Papervision Bug too... It should be easy to check, I'll do that]