As I can see from your attached pictures - you are using similar code to the "Advanced Templates" demo
However as you can check this per yourself - when you try to create an appointment with End Time which is lower then start time - a corresponding error message appears and the appointment is not saved. After further inspection I noticed that the issue appears according to the way the RadScheduler is bound. In the demo it is bound to XMLProvider but when you bind it to SQLDataSource - the issue appears.
Could you please tell me by which of the ways your RadScheduler is bound?
All the best,
the Telerik team