Looks like a rear main seal. That sucks, that's not to uncommon for the 3.6. I have done a few of them throughout the FCA fleet of vehicles.
What I find odd about the 3.6 rear main seal housing is that there is enough play in it, that when you install the housing to the block, you can actually create a worse leak. Then the job has to be done again
This is the first time I've ever heard of the rear main seal of a pentastar being a semi known problem. This engine seems like the sole thing Chrysler and FCA do correctly. Very happy it hasn't bothered with garbage or unreliable tech like DI, cylinder deactivation, etc. Might just get Japanese-level longetivity out of one, even if the same cannot be said for the rest of the vehicle.It's nothing like the 4.0 rear main seal leak. It happens but not like that. With the 4.0 it is/was not if but when will it leak. The 3.6 is usually fixed and then its good for a long time. Knock on wood haven't seen any return leaking again