I have seen leaks with MLS gaskets. I have a slight coolant weep on my 3.8 now. And a few years ago on my Evo 3 swap I had a major oil leak. In that case I thought I had lost a piston since it was major smoke out the exhaust. Turns out the gasket had settled and the oil feed to the head ran right between layers into a cylinder. Once I understood the failure I washed the gasket, reinstalled it and pulled the torque up to 100 lbs. It is flawless now.
I expect on my 3.8 the DOHC heads were not smooth enough for the MLS gaskets. I might go in and pull the torque up a bit on them just to be sure the bolts are not settling.