I'm having a similar issue with the constant updating (I only made it to 72% last time I logged in before my wifi crapped out and/or the download failed), but now it goes to update, it just sits there in "Preparing" mode and never moves to 'unpaused' and start the download again. I also don't have the dropdown option within the 'Manage' button to reset the cache.
When I try to cancel 'preparing' a message pops up that tells me to "Close your game first (btw it's not open, it's being prepared to open?). You must close your current game session before exiting the app."
HELP!