I'm having similar problems with the notification center except I have duplicate entries. On the calander app I have only selected the icloud calenders. In the calander app all is as i would expect. However in notification center one calander is showing duplicates but the others are okay??????
I find that by entering notification center and clicking on a calander event that appear to turn on thecalanders from my mac when i only want icloud calanders. Once the dupilcate is on my iphone the duplicate entries work thier way through icloud and back to my mac. I then have to go back into the setting on my iphone calander and turn off all the mac calanders, thus correcting everything on icloud and my mac.
Notification center appears to have a glitch, or I'm just being stupid.
I tried turning off all calanders on my iphone. Entered notification center and there were still calander entries showing. If I click on an entry it takes me to the calander app and the entry is in there. I then look to see what calanders are showing and it appears to have turned on the clanader for which the entry was made. As nearly all my entries were made on my mac I can see this being a reoccuring theme.