Seems like it’s the night for a braindump over the last couple of weeks…..

Hotfix 923632 will do the job.

be sure to follow these steps after applying hotfix 923632:

1.  Open regedit and go to HKEY_LOCAL_MACHINE\SYSTEM\CurrentControlSet\Services\BTSSvc$<HostName>

Make sure host name is the name of the BizTalk host which is publishing messages which
are routed to multiple req/resp subscribers.

2.  At that key, add the DWORD value AllowMultipleResponses and set it to a value
of 1.

Restart the host service after making this change.