iOS: Tapping Update in App Store just launches the app I am trying to update my apps but cannot.

When I tap the update button in the App Store it simply launches the app, not triggering the update download.

I have a 5c running iOS 7.0

Would anyone know how to fix this?
Tap on the app icon to launch the full product page, and click the "+Update" button there, rather than the "Update" button on the list of updates.

The former works for me, the latter behaved for me as you described.