Almost all the screenshots taken on the 28th demonstrate the glitch. It just randomly transpired as I walked out of the main camp. Saving and reloading fixed it however.
I didn't go through them all, but the first one with the problem looked liked tearing. I haven't seen that before in TW2, but the usual cause is the vertical sync setting. Try turning it on, if it isn't already.
I've seen this sort of behaviour when fighting rotfiends, and using the Heliotrope sign; their heads would get all weird and float around all over the place. I have never seen it happen in other situations, however.
I got it all of the time in DA2, with a video card that was about to fail. I hope for your sake it isn't that. Have you checked your running temperatures recently? What driver version are you using?