Why can't I delete Reminders?

[Windows Central Question]

Why can't I delete Reminders

Hi,

I'm using Win10 mobile fast ring on a Lumia 735.
Everything is smooth but:

I set um 3 sets of recurring reminders via Cortana.(Mo, Thu, Sa 6 or 7 pm, weekly).
Windows phone added them to my calendar.
I deleted them in Cortanas notebook.
Windows phone kept them in the calendar. I can open them, but not change or delete anything. They disappeared from Cortanas list though...

How do I get rid of them?

Thanks!