Are you guys on 9.0.2? And did you originally restore your phone from backup when you got it?
I ask because Apple just turned on App Thinning with the 9.0.2 update. If you aren't aware of what that is, it's where an app installs only what is specific to your device. If you have an iPhone, you are not getting the entire app install that also includes everything for the iPad and so on.
My guess is that if the answer to both my questions is yes, then you have a full version of the app installed and App Thining is coming in to play here.
Just my guess.