Not a miracle. Probably the new fluid that was used didn't have quite the right additive pack it needed ...even though it supposedly was supposed to have. Or it didn't mix well with some of the fluid which was still in the trans before (or varnishes which mixed in the fluid). Obviously the shudder fix which is a sort of a friction-modifier, adjusted the fluid accordingly.
I've (and many others) have experienced shudder in different ways, and different vehicles. One time (for me) after replacing tranny fluid with Havoline fluid. Shudder occurred. I removed Havoline and and went with a different brand Trans fluid that HAD anti-shudder compound in it, the shudder went away. I've also used a different additive pack too on a different vehicle in the past and had it eliminated the shudder. Transmissions never failed. Just one of those things.
You'll probably never have a problem with your tranny. I wouldn't lose any sleep. Thanks for posting back your experience. Good to know for all Ram owners.
Question: Just imagine how many car/truck owners had their trans fluid changed, shudder occurred, and they ended up trading the vehicle in (for new), or bought a new transmission thinking it was failing?!!