Strange. I started the sim normally from the xbox app, and got the splash screen. Then I restarted the sim from my -fastlaunch exe shortcut, and now the splash screen shows... It didn't pop up before until I launched it normally. Go figure. 

I noticed this yesterday for the first time as well but I am in the beta. I usually click my batch file with fastlaunch and go back to a web browser while the sim loads so can't say how long it's been there.