When using jQuery Validation in your forms, particularly with jQuery Unobtrusive Validation, the Kendo controls don't behave well from a styling perspective. In order to get things to work, you need to use a script like the one from this example:

https://github.com/telerik/kendo-examples-asp-net-mvc/blob/master/kendo-input-widgets-validation/KendoInputs_Validation/Views/Home/jQuery_KendoMvcValidate.cshtml

It would be nice if this script/support was better documented and potentially included as a supported mechanism rather than something each customer has to implement and tweak individually.