Just thought it’s worth reporting that this is happening on my 4.13 project as well (splash screen works fine on iPad but on iPhone 6S Plus it shows the splash for a split second, then black screen until the map loads…). It used to work fine a few months ago (I did a lot of stuff in between - upgraded engines, converted to a code project), but from the sound of this post it must be the iOS 10 upgrade that has changed something.
However I’m releasing shortly I may just go for the startup movie workaround as well (quicker than trying to debug this).