Understand that you have to go to the caldav item and click on it before the calendar appears in the calendar app. How do I enable it by default without having to click on it? Any where in the code that I can modify to do so?
I think it was related to an OwnCloud problem that also lead to degrading contact pictures in my case. After updating OwnCloud from 7.0 to 7.0.1, the issue with the contact pictures is gone and since then no speed dial assignment got reset. I also updated DAVdroid to the current version in between.