FD_ALL2 throws NPE

Exception in thread "jgroups-28,TEST4,192.168.123.100:Reciever-18" java.lang.NullPointerException
        at org.jgroups.protocols.FD_ALL2.lambda$new$0(FD_ALL2.java:83)
        at org.jgroups.util.MessageBatch.replaceIf(MessageBatch.java:220)
        at org.jgroups.protocols.FD_ALL2.up(FD_ALL2.java:186)
        at org.jgroups.stack.Protocol.up(Protocol.java:372)
        at org.jgroups.stack.Protocol.up(Protocol.java:372)
        at org.jgroups.stack.Protocol.up(Protocol.java:372)
        at org.jgroups.protocols.TP.passBatchUp(TP.java:1274)
        at org.jgroups.util.SubmitToThreadPool$BatchHandler.passBatchUp(SubmitToThreadPool.java:140)
        at org.jgroups.util.SubmitToThreadPool$BatchHandler.run(SubmitToThreadPool.java:136)
        at java.util.concurrent.ThreadPoolExecutor.runWorker(ThreadPoolExecutor.java:1149)
        at java.util.concurrent.ThreadPoolExecutor$Worker.run(ThreadPoolExecutor.java:624)
        at java.lang.Thread.run(Thread.java:748)