I start my RPC server v7.1.1 under OS/390 with parameters:
RPC=(ACIVERS=5,TRANSP=(ACI,NET),MAXBUFF=28,RPCSIZE=32,
SERVER=ON,SRVNAME=NATWEB,SRVNODE=ETB112,NTASKS=10)
When I try to shutdown server, job is not ended. With NTASKS=1 job ended correctly.
Your Natural batch load module needs to be re-entrant. Use ADALNKR instead of ADAUSER in the link of the dependent nucleus.
see documentation under “Considerations for Mainframe Natural RPC Servers with Replicas” http://techcommunity.softwareag.com/ecosystem/documentation/natural/nat424mf/rpc/start.htm#start_Considerations_for_Natural_RPC_Servers_with_Replicates