The latest update of Chrome browser Version 33.0.1750.117 breaks the radgrid vertical scrolling with these settings:
<ClientSettings AllowColumnHide="True" AllowKeyboardNavigation="True">
<Scrolling FrozenColumnsCount="1" UseStaticHeaders="True" AllowScroll="True" EnableVirtualScrollPaging="True" />
</ClientSettings>
Couldn't reproduce in the latest Version 38.0.2125.111 m of Chrome and Q3 2014.