They all do the same thing, not just Ram (aka Fiat).
Had a good friend of mine buy a lemon Mercedes. They gave her 100,000 mile warranty for free, but she had it in the shop every other week.
They never did figure it out. It happens to all brands. Somebody is not happy.
The good thing is, there are other brands out there ! You have a choice where to spend your money. The problem starts where you've already spent your money, and there is no support from the manufacturer.
And yeah, that guy was not using diesel oil in his diesel truck. Total moron, just to save 12 bucks on DEF consumption.