Wastegate noise - What is considered normal?

[DubVBenz]

I have a 24 1500 LZ0 that has had to back to the dealer a few times to fix failed NOx sensors, one DEF injector and associated components. I only purchased in January and got it finally fixed in mid March. Around that time it got warm enough in Virginia for me to start driving with the windows down, and I've noticed an incredible amount of hissing at low throttle (around 1800-2100 rpm) and blowoff sounds as the engine approaches a new gear. I've only ever owned mercedes diesels (all sedans), and none had similar noises.

I don't really care about the sound, but after reading https://www.duramaxforum.com/threads/lz0-wastegate-“swoosh”-sound.1027787/ , I started to consider that perhaps the replacement of components introduced an exhaust leak or something else that is contributing to the sound?

Again, this may just be normal behavior on these LZ0s and it was bad timing on me retrieving it from the dealer when it finally got warm enough to hear it, but I wanted to check. I did scan it a couple of days ago with a Autel and found no codes.

If there's enough debate about what is normal vs not normal, I'll see if I can record it.