"knock" noise on acceleration

Hey guys,
I have a brand new car listed above it has 5,400 km. Purchased the vehicle in March 2017. It has been about two to three months I have realized there is a noise each time I accelerate with the car. The noise happens once only and is not continuous. I have tried to piece as much information I can about the issue and I have this:

- the noise sounds like a light "knock" coming from the right side of the car, not quite sure if it is front or rear (dealership service has looked into rear and have not found a problem, will explain later).
- when I turn on the car and put the car in drive and begin to accelerate, the noise always happens at twenty nine to thirty km (always that km).
- it happens regardless of direction, going straight or turning.
- as mentioned this sound happens once and never again until I shut off the engine and re-start the car to drive off again (regardless of time interval of car being shut ex. I have gone to the corner store heard the noise, parked the car once getting there, stayed in the store five minutes, get back in the car took off and the noise happens again like always).
- if I apply my brakes before twenty nine to thirty km, the noise will still happen after I get back up to twenty nine to thirty km.

I have been in and out of the Hyundai dealership garage I bought the car (because of the warranty). So far they have checked the rear right end of the car and not solved the problem, they have changed:
- the muffler, close valve and viscous coupling in the differential.

Need any help I can get to take back to the dealer as they are out of ideas, this is getting very frustrating so I apologize for the story book, but if I can get any help at all you guys are the best!

Thanks,
Phil