DateInputSetting in InputManager does not behave as expected.

Use  the code and steps below:

<telerik:RadInputManager ID="RadInputManager1" runat="server">
    <telerik:DateInputSetting BehaviorID="BehaviourFormatHeure" DateFormat="HH:mm:ss" Validation-ValidationGroup="GroupValidation">
        <TargetControls>
            <telerik:TargetInput ControlID="txtHeureDebut"></telerik:TargetInput>
            <telerik:TargetInput ControlID="txtHeureFin"></telerik:TargetInput>
        </TargetControls>
    </telerik:DateInputSetting>
</telerik:RadInputManager>


When  type 5 and quit the input field, it works : 05:00:00 appears
When  type 512 and quit the input field, it works too : 05:12:00 appears
When  type 05:12:27 and quit the input field, it works again : value is unchanged
But when type 051227 and quit the input field, an error is indicated