FIX: System.NullReferenceException error in WCF-SAP adapter when it receives an incoming tRFC in BizTalk Server

Consider the following scenario:

• You use the Windows Communication Foundation (WCF)-based SAP adapter to connect BizTalk applications to an SAP database in Microsoft BizTalk Server. 
• You have an incoming Transactional Remote Function Call (tRFC) operation through a two-way receive location. 

In this scenario, when the tRFC reply is invoked by using the .NET Connector (NCo), the WCF-SAP adapter might raise an error message that resembles the following:

This issue is fixed in the following cumulative updates for BizTalk Server:

       Cumulative Update 4 for BizTalk Server 2016

       Cumulative Update 6 for BizTalk Adapter Pack 2013

       Cumulative Update 8 for BizTalk Server 2013 R2

Microsoft has confirmed that this is a problem in the Microsoft products that are listed in the "Applies to" section.

For information about the service packs and cumulative update list for BizTalk Server, click the following article number to view the article in the Microsoft Knowledge Base:

2555976 Service pack and cumulative update list for BizTalk Server

For more information about BizTalk Server hotfixes, click the following article number to view the article in the Microsoft Knowledge Base:

2003907 Information about BizTalk hotfixes and Service Pack support