Possible breaking change to MS Graph recurrent exception events

Question

It has come to our attention that a recent MS Graph update has changed the way recurrent event instances that were marked as 'exception' type are restored as 'occurrence' type.

Specifically, as of March 27, 2025, modifying the master event’s dates causes all out-of-series child events to restore their recurrence.

Previously, this was not the case—recurrence was only fully restored when either the recurrence pattern or range was explicitly modified.

This change is causing a breaking issue in our system, as it relies on maintaining synchronization with MS Graph events.

Could you please clarify whether this is the intended behavior? We could not find any related information in the MS Graph changelog.

Thank you for your assistance.