2018 Kia Sorento "thunking" noise in front fender area

2018 Kia Sorento SX AWD with the V6. I have a "thunking" noise coming from the front driver side fender area. When I hear it, I'm driving at low speed, around 35mph or less, over a bumpy surface, or when going around a roundabout. To me, it seems like something suspension related, based on when and where it occurs. I've had it into the dealership twice now, and both times they say they couldn't reproduce it despite me providing them the above information. This time they said they looked and everything was tight, and nothing obvious. Any ideas?