Mystery soft clunk sounds at slow speeds

I have a 2009 SLK350. I had the suspension completely rebuilt top to bottom back to front. After about a week, I've noticed that when maneuvering at very slow speeds, regardless of whether it's polished concrete or parking lot road I get a very soft clunking sound when I turn. This only happens at very slow speed turns usually from the left driver side of the front end. Any guesses?

I will be taking it back to the shop because it should be under warranty but before I do so I just wanted to hear opinions.