Assume that you configure an Internet Web Proxy server to make the on-premise Microsoft Exchange Server 2016 access the Internet resource, for example free/busy sharing between Office 365. However, you may find there are too much internal communication traffic between the mailbox servers that transit through the Internet Web Proxy server. The overload traffic could cause the proxy server unresponsive and Internet connectivity losing. After you apply this update, the Internet Web Proxy server will be able to bypass the traffic within internal networks.
How to get this update
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.