Siri doesn't automatically add events to my calendar

Siri has this great function to recognize calendar events in other apps. This is turned on in my Siri-settings.

When I get an e-mail for example, saying "Dentist appointment on 6 July at 9.00" I see it gets underlined. Normally, you would get a pop-up at the top of the screen, saying: "siri found this event. Add it"

I never get this and would really like to use this feature.

See attachments for an example.