Launch the game, wait for xbox sign-in, go to Settings/Global Resources and activate my selected pack (Natural Texture Pack by Microsoft) (pack validation is error free), go back to main menu and pack is now activated and working fine.

Do nothing but go back to the main menu, shutdown the game, launch the game, pack is still active, do nothing at all, shutdown the game again.

Launch game and pack has been forgotten. This happens very time no matter which pack I use.