Back when I was a kid still in HS, I learned a lot about Mopar automatics. Over the years, I've probably owned 200+ Mopars, most of which were automatics. Both the 904 versions and the 727 versions have this problem, and it didn't go away with the newer OD versions (at least up through 2016). The front drive units seem to have more capacity to accommodate the converter drain back. The drain back still happens and they still can leak outside of the trans, just doesn't seem to be as bad.

Just picture the torque converter with the round shape that is full of ATF as it operates. The fluid passes from the converter to the trans body through the center hub. After you shut the motor off, its pretty much the metal on metal sliding valves in the valve body the keeps the fluid in the top part of the converter. As those parts in the VB wear, they allow a small amount of fluid to drain out of the converter. That fluid has to return to the trans pan. Under normal operating conditions (motor running, trans working), the fluid level in the trans is just below the pan gasket. The converter can, and does drain until the fluid level inside of it is below the lowest part of the center hub (about 2 quarts worth), all of which brings the pan fluid level above the pan gasket and most of the lower trans seals. Bad seals means an ATF lake under the car if its sitting on a solid surface the fluid can be absorbed into. The time frame for this to happen can be as short as a few hours, or weeks depending on the condition of the VB. You may not see the problem if the trans is well sealed, but bet on the fact it is happening.

So do yourselves a favor, the first time you start up your Mopar auto trans after its been sitting, take 30 seconds with the trans shifted into neutral, so the torque converter can refill, before you take off.

Just trying to pass along some of the things I've learned along the way. Its your choice to take advantage of what I've learned, or not.