UpdatePanel works great in all browsers except IE8

Question

I'm using a timer triggered update panel which works perfectly under the latest versions of Firefox, Opera, and Safari. However, in IE, it sometimes works fine (just the panel updates without flicker elsewhere), but often the whole page starts to flicker after a while.

I'm using a control to encapsulate this logic and the control is used on all of the pages on my web site. Here's my code. Any suggestions? and Thank you.

<%@ Control Language="C#" AutoEventWireup="true" CodeBehind="QuoteControl.ascx.cs" Inherits="occinc.QuoteControl" %>
    <asp:ScriptManager ID="ScriptManager1" runat="server" EnablePartialRendering="True" AjaxFrameworkMode="Enabled"/>
    <asp:UpdatePanel UpdateMode="Conditional" runat="server" ID="UpdatePanel1" >
        <ContentTemplate>       
        <div id="content-side2-three-column">
                <%--Data Source Controls--%>
                <asp:ObjectDataSource ID="ObjectDataSourceQuotes" runat="server" SelectMethod="GetAllQuotes" TypeName="Quotes"></asp:ObjectDataSource>
                <asp:GridView ID="GridViewQuotes" runat="server" AutoGenerateColumns="False" DataSourceID="ObjectDataSourceQuotes"
                    BorderWidth="0" BorderColor="white" OnRowCreated="GridViewAllQuotes_RowCreated">
                    <Columns>
                        <asp:TemplateField>
                            <ItemTemplate>
                                <h2 id="<%# Eval("id").ToString() %>">
                                    <%# Eval("Author") %>
                                </h2>
                                <q lang="en-us"><%# Eval("Content")%></q>
                                <br />
                                <hr />
                            </ItemTemplate>
                        </asp:TemplateField>
                    </Columns>
                </asp:GridView>
        </div>  
        </ContentTemplate>      
        <Triggers><asp:AsyncPostBackTrigger ControlID="Timer1" EventName="Tick" /></Triggers>
    </asp:UpdatePanel>            
    <asp:Timer ID="Timer1" runat="server" Interval="5000" />             
    <div class="clear"> </div>