How to reproduce : 

1/ Create a recurrent event (on a week for instance) : 

In the example below, end of recurrence is on 25/02. 

2/ Drag and drop the event of 23/02 to next week. (so after the end of recurrence)

3/ Select "All events" to the question. 

4/ Eve1 has disappear : there is no more event of Eve1. 

=> 

Either a confirmation message shall be added. 

Or when a drag and drop is performed end date of recurrence shall be also moved.