Addendum...
Cool! I'm very glad to hear this about your 2.9 i9 32GB 1TB MBP. This gives me hope for my third 2018 MBP.
Actually, I'm feeling a little sorry for the Apple engineers. They receive a MBP and it passes all of their hardware and software tests, so what do they do? They probably leave it running on their desktop along with the other dozen computers they are tasked to fix. Maybe once an hour they touch the machine, in rotation with their others. Under these circumstances it would be nearly impossible to detect these rare, random, and intermittent errors.
Both of my 2018 MBPs passed the "on machine" hardware tests without any errors -- and yet I found dozens upon dozens of errors during continuous use (my typical use, coding, actually touching the machine continuously, is roughly 18 hrs a day 7 days a week, give or take). And this reminds me of an earlier post in this thread where the poster took his/her MBP to the Apple Store and was called back a few days later to pick it up. The store hadn't done anything to the MBP since it passed their hardware tests and they hadn't seen any problems occur. When the customer picked up his/her machine, he/she opened the lid and started the laptop...almost immediately the MBP suffered a kernel panic thus demonstrating for the Apple Genius that his/her machine had problems.
Now I'm sure that Apple engineers have more sophisticated tools to test and stress the 2018 MBPs. Personally, I, for one, setup a chron job on another machine that ran an nmap attack against various ports on the 2018 MBP every five minutes all day long in an attempt to detect the WiFi connectivity issues. But who's to say than an nmap attack doesn't on its own eliminate the intermittent WiFi connection issues, or that I chose the proper ports to test? So, once again, I'm certain that Apple's engineers have more sophisticated methods and equipment for finding and fixing errors on the 2018 MBPs, but it still may be difficult even for Apple to find rare, random, and intermittent problems.
(And while I uploaded over 900 files -- 6+GB of data including pcap packet capture files taken during WiFi disconnections -- and explained in detail to the Apple Senior Advisors the nature of these problems and why they were serious, I'm not positive how much of my documentation actually landed in the hands of an Apple engineer. The Senior Advisors, who were not familiar with ssh, rsync, gpg2, nmap, wireshark, etc., may not have actually passed on my documentation to the engineers. I tried to explain to them why this documentation was precisely what the engineers would want to see, but I don't know how successful I was in my explanations. In fact, I'm sure I did a rather poor job and wasn't clear enough at all in my explanations, otherwise the following would not have occurred. At one point I was asked to take my 2018 MBP to an Apple Store and have them attach it to a WiFi router that was, and I quote, "precisely 20 feet away, no more, no less". I explained that my MBP would pass this test, that simply attaching it to another WiFi router, even one precisely 20 feet away, would not cause the rare, random, and intermittent WiFi connection issues that I had documented...the MBP would have to be in continuous use for days in order to catch these WiFi connection issues, even with the router 20 feet away. Not only that, but I explained that the nearest Apple Store to me is over 320 miles away which is at least a 6 hour drive, depending upon the traffic on I25. So this test would not only be superfluous but it would also be very difficult and expensive for me to accomplish.)
