Resolution:
PROBLEM: Users connecting to Object Service Broker (OSB) via VTAM may encounter ABEND U4088-xxx  (xxx varies depending on  maintenance level).
        
         The job log may also display the following messages:
                 S6BNC890W LOSTERM EXIT ENTERED, APPLID='xxxxxxxx', LU='xxxxxxxx',
                 S6BNC995E VTAM SYNAD EXIT ENTERED, APPLID='xxxxxxxx', LU='*UNKNWN*'
                 S6BNC998E UNABLE TO CLOSE VTAM ACB, APPLID='xxxxxxxx', R15=X'00000004'
                
CAUSE:
         If a VTAM connection is abruptly terminated, an in-transit message from OSB to the disconnected entity is not handled properly by recovery logic and causes the ABEND U4088-xxx.
        
SOLUTION:

         The problem will be fixed in the next release of TIIBCO Object Service Broker for z/OS.

Reference:  CR 1-8MH2EN

VTAM users of Object Service Broker (OSB) may encounter U4088 abend