TouchID for App Store purchases doesn't work after turning phone off and back on?

TouchID for unlocking my iPhone 5s works 99.9% of the time. It's fantastic. However, using it to authorize App Store purchases, NOT in-app purchases, is less fantastic. In my case, it seems like every time I turn my phone off and back on, the phone forgets it's can use TouchID to authorize app purchases. I have to go into Settings -> General -> Passcode & Fingerprint -> (enter my passcode) -> Fingerprints -> iTunes & App Store, and turn that off. Then I have to turn it back on and enter my Apple ID password. Not exactly a quick procedure. The good news is that once I turn it back on, it works like it's supposed to until I turn my phone off and back on again. If it can remember to use TouchID for unlocking the phone, why can't it remember to use TouchID for authorizing App Store stuff? Am I missing something?

Anyone else experiencing the same thing and/or have a solution? Thanks!