The problem is caused by the RadTextBox. It can be reproduced with the following code:
<body>
<form id="form1" runat="server">
<telerik:RadScriptManager ID="RadScriptManager1" runat="server">
<Scripts>
<asp:ScriptReference Assembly="Telerik.Web.UI" Name="Telerik.Web.UI.Common.Core.js" />
<asp:ScriptReference Assembly="Telerik.Web.UI" Name="Telerik.Web.UI.Common.jQuery.js" />
<asp:ScriptReference Assembly="Telerik.Web.UI" Name="Telerik.Web.UI.Common.jQueryInclude.js" />
</Scripts>
</telerik:RadScriptManager>
<telerik:RadTextBox runat="server"></telerik:RadTextBox>
<div class="divEl"></div>
<input type="button" value="Test" onclick="test()" />
</form>
<script>
function test() {
var input = $('.divEl');
$(input).wrap("<form>").closest("form").get(0).reset();
}
</script>
</body>
</html>
Problem is resolved in the RadTextBox's code.