When Property tag is used like [Property context="autofill" type="content" format="MMMMM d, yyyy" field="generaldateone"] in Menu or Personalization component, the date is rendered as "O 12,2012" instead of "October 12, 2012"
WCM is using a java class java.text.SimpleDateFormat and this appears to be an issue with this class although MMMMM is supported. The issues appear to be with the value returned by Java
Resolving the problem
As a workaround, developers could use format="Date_LONG" or format="MMMM d, yyyy" instead of format="MMMMM d, yyyy"