Having been a machinist I too can see a small flaw occurring every so often with many not being caught until they flare up as a leak or trouble. My '03 has a few seeps but they are far from the oil throwing my old Pan and Shovel heads did.

 

Sorry, I'm with Dan on this one. If it were a common problem - I'd agree with lack of QC. But this seems like a one time issue. In case you don't know - these things are mass produced and for the most part only assembled by hand. Boring, tapping and all manner of other machining processes aren't. I don't see a machinist checking every thread depth or bore for problems, and yet most machining is "generally" within specs.
Besides - it's a 6 year old bike - when is Harley off your leash?

 

JB Weld !!!