I had my car into the shop about 5000 miles ago for an alignment. After the work was done a thunk noise started coming from the rear of the car. I had this looked at but no one can find out what is causing the issue.

Sound almost like a loose shock mount?

Visual inspection revealed a possible LR control arm mount loose. There was some play but it did not seem to be enough to cause the thunk. It is only noticeable when driving real slow and when the car is on rough pavement. The Tech told me it was not dangerous, just aggravating.