Recurring Events reappear after Deletion of the last Event

JEM 2.2.1
Joomla 3.7.2

I tried to delete the last event of a recurrence. The Recurrence is weekly up to 5.7.2017.
After de-coupling the entry of 5.7.2017 from the recurrence (with save), I deleted it. Next day, the Recurrence created again an entry for 5.7.2017.
Next day, I deleted the 'recurring entry' of 5.7.2017 and emptied the Trash bin.Today, the entry was back.
Now I deleted it again and checked the DB. There is no Event-Entry in the SQL-Table. I hope it won't be created again.
Could you please verify if the deletion of recurrent event works correctly ?
Thx.