When you have another scrollview in tabs the native event - scroll-to-top on status bar tap - is suppressed because there are more scrollviews on screen: https://developer.apple.com/library/ios/documentation/UIKit/Reference/UIScrollView_Class/index.html#//apple_ref/occ/instp/UIScrollView/scrollsToTop
The ScrollView inside ScrollableTabBar.js should have set the scrollsToTop={false}.