That's very strange. I've been useing Mobil 1 for over 20 years now, in all my Chryslers (Mopars are all I've ever owned) and have never had any problems with it. I've asked different Chrysler service tech's at different dealerships and they have all said the same, that Mobil 1 is just fine to use. The first car In used it in was a '92 Le Baron with a 3.0 V-6 that was two years old when I bought it. The first thing that I noticed was the the engine started running a lot quieter and smoother. Had over 150,000 miles on it when I traded it in, and it was still running strong.
Bought a 98 Dodge Dakota two years ago. First oil change I put Mobil 1 in it. This truck has 100,000 miles on it. One of the very first things that i noticed was that the gas mileage went up. Not a real big increase but still an increase. Truck is running a lot smoother also.
My brother has replace all the lubricants in his Dodge with Mobil 1 lubricantes, oil, transmission and rearend. He's had nothing but good results. He's had this car for ten years.
So I don't think I'm going to stop using Mobil 1 anytime soon. The one thing that I love about Mobil 1 (all synthetics) is that when the engine is cold, winters here in northwestern Ohio, the oil starts to flow as soon as the engine starts. It's not effected by the cold the way regular motor oil is. I'll continue to use it.