Q: Differential leak while speeding

My Solstice with LSD - limited slip differential has less than 3700 miles on it. I had the rear end serviced at the dealership about 17 months ago. I recently noticed a slight leaking and dust accumulation of the differential. So I cleaned it and it drove easily with no problem. I drove home Thursday on the freeway at 90 mph. When I got home I could smell and see the rear end leaking. I topped off the oil and tried driving it at a normal freeway speed to recreate the leak. Today I drove up to 115 mph, pulled over to the side of the road and it had leaked onto the road. The differential and exhaust were oily. It’s coming down from the top left. The metal vent area is dry. Is the vent stuck open blowing a mist of oil at high speeds? The right axle seal is dry, but maybe it’s doing the same thing. I can’t hear or feel any grinding or chattering when I turn. Do you have any thoughts?