In an Exchange Server 2013 environment, when you disable Unified Messaging (UM) call answering rules by setting AllowCallAnsweringRules to False in the UM mailbox policy, you find the policy is not honored and the UM call answering rules are still enabled for the UM mailbox.
This issue occurs because the setting AllowCallAnsweringRules is not evaluated when UM Call answering rules are enabled.
Cumulative update information
For Exchange Server 2013
Microsoft has confirmed that this is a problem in the Microsoft products that are listed in the "Applies to" section.
Learn about the terminology that Microsoft uses to describe software updates.