Can anyone give me any on advice with this..

I play on iPhone, for the last few weeks nearly every time I open the app it has to do a full reload of all the dragons, in the past I only noticed it do this once every few weeks. It?s been a real pain time wise but I?ve just noticed my data usage and it?s meant I?ve used up to 2gb of data a day playing DS. Over 30gb this month alone. Which has now run out! Is this a bug with the app or a problem with my phone? Haven?t seen any problems with other apps or games.

Any advice would be helpful, I don?t know what to do...