Resolution:
This RTserver trace message indicates that RTserver is checking if the client indicated has the server specified in its suspended server list. This "suspended" condition is not a literal suspension of the server indicated. This is just a suspension of message processing on a specific subject for the server client pair that occurs as part of the protocol between servers for GMD subscription management. The indicated server is still processing messages, it just gets suspended at the client level if needed. You would see an additional message indicating that the RTserver was removed if it had actually been marked as suspended.

{SRV.SMR./_node0_PID} Checking for suspended server /_node1_PID in client /client_unique_subject