notification center freeze/crash

I am repeatedly seeing a freeze of Notification Center. I swipe left to bring it out, the widgets appear on the right of my screen, then the widgets freeze (and if I drag the cursor over the widgets, I get the pinwheel of death). I can fix the freeze temporarily by Force-Quitting the Notification Center process in Activity Monitor (which is labeled in red as nor responding and is pegged at about 100% CPU use). Every attempt to re-invoke results in the same freeze. I can fix the problem by trashing notification center prefs (/Users/username/Library/Preferences/com.apple.ncprefs.plist) and then restarting.

Notification Center then works for a while, though I have to re-allow (or deny) various apps access to Notifications over again. However, after a while, after enabling or denying a random app's access to Notifications, the freeze recurs. There seems to be no consistency to which app and whether I allow or deny (I checked).

I will be submitting a bug report, but I also thought I would reach out to see if others have seen this or if others have fixed it.

best,

jason