Resolution:
RTserver reports the following:

{SRV.SMR./_RTserver_unique_subject} TAL-SS-15382-W TsmrCbServerSrvGmdResume: can't find client </bar/_RTclient_unique_subject> in app &ltproject_name>. Can not resume gmd buffering.

When RTclient first publishes a load balanced or GMD message on a particular subject the RTserver will stall the connected publisher and all receivers subscribing on that sdubject. (Stalling prevents the clients from publishing). It then sends a GMD_INIT message out to the other RTservers. When it has received back all the GMD_INIT replies it then tries to resume all the stalled RTclients. The error message implies that the named RTclient had disconnected after the stall, could no longer be found so therefore it could not be resumed.  This is only a (W)arning message as opposed to an (E)rror, therefore RTserver simply reports the issue and continues.

For additional information see the KB article entitled, "What does the message "Suspending GMD processing for client X from server Y and subject /foo" mean? ".

What does the error "Can not resume gmd buffering" mean?