Recently we observed that our plugin registered on the Delete message of appointment on the PreValidation stage was not getting triggered when we were deleting or updating the occurrence of the Recurring Appointment.
For both of the below operations, our plugin was not getting triggered. The plugin had the logic to delete a few associated records to the appointment record.
Delete operation – This deletes all the existing appointment.
Recurrence Update –This deletes the existing appointment and creates new appointment records based on the new recurrence.
On trying out different things, we saw that the plugin was getting triggered if registered on the PreOperation.
For testing, we registered a sample plugin that throws the InvalidPluginExecutionException and saw it getting triggered in case of PreOpertaion as shown below.
Hope it helps..
Nishant Rana's Weblog 