I was able to confirmed this "feature". I was running fine after receiving the 4.3 update, no issues with the stock TouchWiz (TW) until I tried to help out another user with their TW crashing. (Re: Touchwiz not working)
I added the 4x4 calendar widget to the Home screen and whenever I swipe to it I would get the TouchWiz crash message. I can't find anyway to remove the widget because it won't let me go to that page without crashing. The pinching home screen action also crashes so I can't remove the page with the widget on it that way either.
I gave up and just went into Apps setting and clear cache and data of the TouchWiz app. (I Googled the issue and some people were successful in deleting it through other settings, but not me.) Now I have to redo all my home screen and apps drawer changes. I'm sure they will role out an update to either remove that 4x4 Calendar widget or fix it soon.
Edit: Member BeachLizard has a better solution instead of clearing the TouchWiz home settings (cache and data), go into Settings->More->Application manager->ALL then look for Calendar widget, select it then select Turn off option. Verify the Calendar widget is now gone from the home screen. Now go back to Settings->.....->TURNED OFF then select the Calendar widget and select Turn on option. Just don't use the Calendar (month) 4x4 widget until Samsung fixes it.