this is unfortunately a very well known issue :(
For me the only way of solving this is to export with Android Studio and comment out one line (103) from the splash plugin. then it works fine.
there exist a fork of the plugin as well, but then you will need to build the apk with cordova on your own.
If you use the C3 exporter the back-button don't work (only work if you unfocus with home-button and go back)