2018 2500 Cummins hissing/air noise

[NUGNUG]

I have a 2018 2500 Cummins with only 17k miles on it. The other day, while waiting in line for fuel, a hissing sound started out of the blue coming from the engine bay somewhere. The truck has not thrown a code. It seems to only happen when the truck is at operating temperature, I do not hear it when I start it up cold. I checked the intake hose in the passenger fender to see if it had collapsed, and it had not. It was fine. The air intake hoses are all tight going from the air filter box to the turbo. I can't make it happen consistently. When it happens, it sounds like it is echoing through the whole intake system. It's really odd. Any ideas on what to look for will be appreciated. TIA