The valve covers use o-rings. Likely it was pinched/nicked on installation, if installed correctly it should not leak. My vert cyl. intake was nicked when I took it off for a valve check but didn't leak. This kind of stuff isn't worth the hassle of the dealer. Check and replace if neccessary. Always grease the o-rings so they compress and slide smoothly into the bore in the head. Rotate the cover back and forth while pressing down square.