I have heard the same on the shock issues with the 2018 and Specialized is not really
honoring the warranty, even with the oil leaks, they claim they are still functional. I also see where the 2019 changed the bottom bracket and the wheels over the 2018. The 2018 was a learning year and will have problems.
I've worked for a shop in my hometown and raced for them for several years and have been through several epics, as have a lot of others around here and have NEVER heard of specialized not warrantying their brain shocks.
So unless someone actually has legitimate evidence and a good shop representing them, i honestly dont believe it.
I've personally had some warrantied as well with an oil leak which was also losing pressure and it was no questions asked once our shop manager called to ask about it (That was the first call made as well) They just sent a new one and we had it within a few days.
Also, On the topic of discounts, anything over 25% is a fantastic deal on a specialized. Cost is pretty high so there isnt just a massive profit margin for most shops. Cost also varies by how much product a particular dealer can move. So if you're ok with the potential for having to warranty a shock from 2018 (since that was the year model with the most issues as the brain was a new version for 2018) i say go for it if its a good discount. Or you can wait for the 2020 which is what i would personally do. Parts specs should be better and it wont be too much higher of a cost if you can get any kind of a discount from your LBS.