it should not twist unless it loose. if you have a habit of holding the grip right up to the end, make sure the fitter add a couple of layers of tape at the back to get better grip. also check if they use a proper grip activator solution and not petroleum.
if it is loose you will lose your grip easily so its best to re-grip them or have them check if the grip has loosen due to wear and tear or improper installation.
hope it helps......DGman