1) Use this StackBlitz application: https://react-scwx3i.stackblitz.io - This is based on Telerik's own DatePicker React example.
2) Highlight the AM/PM section.
3) Press the up arrow key to go from "AM" -> "PM" -> "AM" - note that for each "PM" to "AM" change, the Day value increments
4) Press the down arrow key to go from "AM" -> "PM" -> "AM" - note that for each "AM" to "PM" change, the Day value decrements.
My expectation is that changing AM/PM values should not change any other sections of the Date/Time value.