Check-In Warning for last Airbnb bookings

I am getting “Check-In Warning - Airbnb booking” mails for every Airbnb booking since a few weeks. None of our guests had problems getting into the flat. So I started to ignore those mails. But today I noticed that the entry keys that are automatically generated are not deleted afterwards. The entry codes list ( has about 10 entries now. 3 of them are current Airbnb bookings. The Airbnb booking list ( shows the current 3 bookings.
Anyone had the same problem or can help me on this?