Oil Leak Question

A question for those experts who have rebuild or assembled a 2.4 L engine.

Last weekend I installed a timing chain on my 2.4L Malibu and while I had everything apart I thought I would fix a few leaks so I bought a cam housing gasket kit and installed it. Put everything back together,shampooed the motor and went for a drive. Have put several hundred kilometers on since , car runs great and no more leaks EXCEPT there is a tiny amount of oil seeping up between the exhaust manifold and the head. When I turn the car off I can see tiny little bubbles of oil between the exhaust manifold gasket and the cylinder head.
HOW IS THIS POSSIBLE??? this is happening at the top of the exhaust gasket and at the bottom. The head gasket is not leaking and neither is the cam housing or cover gasket

I have rebuilt numerous motors (not 2.4's) and am totally perplexed, where is this oil coming from?? Any ideas??

Thanks

Anybody??