Even since purchasing my new 2022 GMC Yukon Denali, it has randomly made a knocking noise under the car behind the drivers seat. It sounds like something gets thrown up and hits underneath the car. It can happen under 30 MPH or on highway at 55-65 MPH. It is startling and loud enough to take notice. Anyone know what this is? The dealer hasn't been able to replicate and doesn't know how to fix.