Slightly rough idle at cold start.

[Shohobo]

At startup after sitting overnight the engine is acting like it is missing...nothing violent just a subtle consistent light vibration and the rpm gauge bounces every so slightly...rpm # seems to be @ normal cold start rpms...right @1K....only happens when it sits overnight....I take a cruise at my lunch hour and no issue at startup..any ideas? 2,000 miles on a 2015 SHO...non PP....9 weeks old...this issue began about two weeks into ownership...any advice or know issues shared would be greater appreciated.