Seen in these scenarios in ER4:
During server startup (the server was restarted after previous graceful shutdown), this error was logged several times:
[JBossINF] [0m[31m20:12:25,912 ERROR [org.jgroups.protocols.UDP] (multicast receiver,ee,perf19) perf19: failed submitting DONT_BUNDLE message to thread pool: java.util.concurrent.RejectedExecutionException: Task org.jgroups.protocols.TP$SingleMessageHandler@7a718788 rejected from java.util.concurrent.ThreadPoolExecutor@66f4f3ee[Running, pool size = 300, active threads = 300, queued tasks = 0, completed tasks = 1130]. Msg: RequestCorrelator: id=200, type=REQ, id=125094, rsp_expected=true, FORK: ee:web, NAKACK2: [MSG, seqno=123637], UDP: [cluster_name=ee]
It had no impact on the client though.
JBEAP-2944 <node> failed submitting DONT_BUNDLE message to thread pool during server startup