It may just be a bad oil pan drain plug.
The drain plug has its own washer built in. It will flatten out eventually and cause it to leak.
I went into shock the first time i crawled under and saw all the oil coating everything...
I ran to the parts store and picked the drain bolt in the picture and replace the original and it has been perfect.
Not a single drop of oil has been past it.
Here is what to look for and the plug to replace it with..
This is two pictures of the original plug... You can see how the rubber gasket it just flat...
Here is the replacement...