Any news on this one. I'm planning to bring mine in soon to a different dealer for this issue.
I always go prepared for battle if I go to a service center at a dealership. If confronted with the "that's a normal sound" when they reply back, just go ahead and find another 2013 (or any other 5.0L) on their lot and ask them to start it up and drive til warm, bring them both back, side to side, and record both yours and the other car. If your car makes the noise and the other one doesn't, THEN have them EXPLAIN why the noise is normal. Ensure to get their face and name in the video so, the name of the service manager, his face too. Then call Deysha and upload the video to YouTube for all to see. I believe they would then go-down-on-you to fix the car. When presented with evidence that shows' it's NOT normal and another car of the exact same type does NOT have that noise, you have them ON RECORD. Of course, then they may accuse you of not changing your oil or using incorrect oil, or driving your car too hard, or some other non-sense. That noise is fairly common, and there are lots of videos on this board with it.... and I'm sure the links will point you to the right solution. Some had serious issues warranting a rebuild, some didn't. What your particular issue is, remains to be seen.