Well I have to bump this thread since after we can finally login and play Greymoor to see that the problem still exists...
It also happens on more than just weapon switch. Any time you draw a weapon with 1h+shield using the RT (light/heavy attack) it does this. If you use LT (block) it doesn't, so I'm trying to get used to unholstering weapons with LT. But I shouldn't have to, and it still glitches out when swapping weapons.