» Thu Dec 15, 2011 9:24 am
You don't need to use a shield with your matching set, and you can even use a light shield and still get the benefit when it's working properly. All I can suggest is unequipping, saving, restarting your game, loading, and then re-equipping.
Incidentally, what's your armor rating with the set on? If it's more than 567, or 547 with a shield, you've hit the damage reduction cap and won't get any benefit from an increased rating anyway.