Workaround - avoid scrollbar decoration:

<telerik:RadFormDecorator runat="server" ID="rfd1" DecoratedControls="All" Skin="Default" ControlsToSkip="Scrollbars" />

Reproduction Steps:

1) Open the code below in Chrome with Telerik UI 2015.2.729 version.

2) Scroll till you reach the second blue div with the button.

3) Click the button to make an AJAX request.

4) Actual - the page is scrolled to the end of the first inner div. Expected - the page should not be scrolled.

       <telerik:RadFormDecorator runat="server" ID="rfd1" DecoratedControls="All" Skin="Default" />
        <div style="width: 600px; height: 500px; border: 3px solid green; overflow: scroll;">
            <div style="height: 1000px; border: 3px solid red;"></div>
            <asp:UpdatePanel ID="Updatepanel1" runat="server">
                <ContentTemplate>
                    <div style="height: 300px; border: 3px solid blue;">
                        <telerik:RadButton ID="RadButton1" runat="server" Text="Click" />
                    </div>
                </ContentTemplate>
            </asp:UpdatePanel>
        </div>