We have the same problem and are facing it currently in production.
We rolled out an update to the AppStore. After upgrading the current version, say version 1, to version 2, the user still sees the splash screen from version 1. However, if the user uninstalls either version 1 or version 2 and afterwards downloads the newest version 2 from the AppStore, she sees the splash screen from version 2.
I renamed the splash screen in the Xcode project, but still the error persists.
Have you found any solution to this problem?
Problem is that launchscreen (splash screen) is stored in cache and not cleared when you upload without deinstalling first.
There may be some trick, like renamin the image iused and removing the old one from xcassets
Another way is to propose users to offload (not remove) the app. So they will not loose their user data.