[mkrntz]

When I activate attending events in my calendar on my Lumia 930 they all are doubled. Anyone else get this?

[several potatos]

Same here but I've long since given up on fixing it

[aximtreo]

Try going to Calendar app, tap on the ... and open settings. See if more than the main calendar is checked. I uncheck all the calendars except the one I use.

Hopefully this helps.