Created Unassigned: Visual Studio 2013 MaskedEditValidator not validating dates properly [27589]

When validating, 01/05/2013 is a valid date where 01/13/2013 is not a valid date.
Code:
<asp:Label runat="server" AssociatedControlID="ShowEndDate" CssClass="col-md-6 control-label">Show end date</asp:Label>
<div class="col-md-6">
<asp:TextBox runat="server" ID="ShowEndDate" CssClass="form-control"/><ajaxtoolkit:calendarextender
TargetControlID="ShowEndDate"
runat="server" />
<ajaxtoolkit:maskededitextender ID="MaskedEditExtender3" runat="server"
TargetControlID="ShowEndDate"
Mask="99/99/9999"
MessageValidatorTip="true"
OnFocusCssClass="MaskedEditFocus"
OnInvalidCssClass="MaskedEditError"
MaskType="Date"
PromptCharacter="_"
CultureName = "en-GB"
ErrorTooltipEnabled="True" UserDateFormat="DayMonthYear" />
&nbsp;&nbsp;