Hi there, I just bought a new iPad Pro with cellular last week. I have been using it at home with WiFi only for the 1st week so everything should have synced. Sure enough, after I activated my iPad to my cellular plan I took out my iPad today to a meeting and the iPad was a sleep all day in by brief case. I came home to notice a 30% battery drain and over 1GB of cellular data getting sucked up for nothing. What a joke! Documents and Sync shows over 700MB. I have turned of use cellular data under iCloud Drive. I also have an iPhone and a MacBook. I will turn of PowerNap,, whatever this issue is, it isn't good. Why would iOS only use cellular data to sync whatever it is syncing during sleep, meanwhile my device has been connected to my WiFi for several days? I also have that annoying setting turned off "Wi-Fi Assist" which is also a data burner!
The only app on iCloud Drive with a significant amount of data on my iPhone in the similar range is Whatsapp. So, I guess I will be calling AppleCare and my cellular provider tomorrow. After a few web searches, it appears others have been experiencing similar issues since iOS 8. Cellular Data Drain down the toilet into the carriers pockets. I guess I sense a cash grab data burn. Seriously, apple needs to fix this among other bugs. iOS 9 has been an uphill battler after I upgraded to 9.2.1 and higher. 9.2 was pain free. The thing is, I setup this iPad as new, so that I wouldn't inherit any bugs from old backups, and the first thing they make you do in store or over the phone is reset and restore as new.
