I was just under my truck yesterday, same thing......, mine was just starting to form a drop, I did have some oil on the lower control arm bracket, very little, something you could see the wind was getting at. I wiped mine up around the axle tube seal and I guess I will wait to see what becomes of it, the shitty thing for me is the closest dealer is 4 hours away.
I had a small drip on the floor on my gararge since shorly after the last oil change (at dealership). When I brought it back for the next oil change I told them about it and low and behold they had to replace some seals in the front diff. it was ofcourse under waranty. So far so good.