Article ID: 2771688 - View products that this article applies to.
After applying the Microsoft Dynamics CRM Online December 2012 Service Update, users may notice that duplicate detection does not run after creating duplicate records in the new form experience. Per the default duplicate detection rules, these forms may include:
However, if additional duplicate detection rules have been created for Opportunity or Case, these rules will not take effect in the new form experience for these entities as well.
(http://go.microsoft.com/fwlink/?LinkId=151500)for other considerations.