The iPhone browsers (both safari and chrome) do not appear to use accelerated scrolling. So as soon as you lift your finger from the screen the scolling stops.
Interestingly, the touch pad and screen of the Asus Chromebook, does not have this problem and scrolling works as expected.
Other websites on the iphone also work as expected when it comes to scrolling.
Not having a good resolution for this really distracts from the usability of anvil apps in the mobile setting.