docs(scheduler): clarify exception dates behavior

Author: marin-bratanov

components/scheduler/data-bind.md

@@ -38,7 +38,8 @@ The scheduler appointments provide the following features that you control throu
 
 * `RecurrenceRule` - (`string`) - the recurrence rule for a recurring appointment according to the [rfc5545 standard](https://tools.ietf.org/html/rfc5545#section-3.3.10). Present only for a recurring appointment, but not for an exception from it. In the data source, there is only one item that determines a recurring event, and the scheduler expands it to render the necessary number of appointments in the UI.
 
-* `RecurrenceExceptions` - (`List<DateTime>`) - a list with the exceptions for a recurring appointment. It tells the scheduler when to skip rendering a recurring appointment because its instance is explicitly changed or removed (deleted), and so it is an exception to the recurrence rule.
+* `RecurrenceExceptions` - (`List<DateTime>`) - a list with the exceptions for a recurring appointment. It tells the scheduler when to skip rendering a recurring appointment because its instance is explicitly changed or removed (deleted), and so it is an exception to the recurrence rule. 
+    * Exception dates are relative to the start time of the recurring appointment, and changing the start time of a  recurring appointment (either through the edit form, or by dragging any recurring event) will update the exception dates to match the new start time. This does not affect exception instances that are already created, because they are separate appointments. For example, let's say we have an event that recurs every day - from Monday to Sunday, uncluding. If we create an exception for Tuesday, and change the start time of the entire recurring event to begin on the Wednesday after that, we will have the exception appointment on Tuesday and a gap on Thursday, because the exception date that was initially Tuesday actually matches the second occurrence of the appointment, which is now on Thursday.
 
 * `RecurrenceId` - (`object`) - the unique identifier of the recurring appointment to which the current appointment is an exception. Must be of the same type as the `Id` field (e.g., a `Guid`). Present only for an exception from a recurrence, but not for the recurring appointment itself.