Kendo UI DateTimePicker is designed to set its value based on the parsed input (value) on blur. When widget format is set to "HH:mm", then it does not have knowledge for the date part and hence the today's date is used. This behavior cannot be changed and you will need to use a full date format (date + time) in order to persist the date and time part simultaneously.
Another option is to use separated DatePicker and TimePicker widgets .Thus user will be able to choose the values separately. Later, you can combine their values in a single Date instance.
Check out the Telerik Platform - the only platform that combines a rich set of UI tools with powerful cloud services to develop web, hybrid and native mobile apps.