Well my new truck has the leak on the passenger side. Taking it in Wednesday. This comes after purchasing a 2.7 lt on Sept 14, and it being in the service center since Sept 16th with a collapsed lifter. Finally, this week, on Oct 14th we agreed to a new deal to put me in a new truck (5.3 ltz), and I even lost a few thousand dollars in the process, but I was ready to have a truck since my brand new one was garbage. Well it turns out my new new one has this leak. It's already been a very embarrassing and stressful experience so far, getting all the "you should have bought a... " crap from everyone, now I get to go through it all again! I'm pretty sure no matter the outcome with this one I won't be buying another GM vehicle. I know I'll get a lot of crap for this but.... my wife's kia Telluride has 13k miles on it and has been and absolute dream, my experience buying a silverado has been the worst possible nightmare. I can't believe they actually put a sticker on these trucks for $50k.
Also mine has a build date of 2/19, so it's not exclusive to those built in 2018.