We have found a thread that is locked is this:

Computer.threadPoolForRemoting [#494987] / waiting for EC2 (DevSecOps Agent) - Linux (i-0b99db4829aeb5474) id=156631640" #13983096 daemon prio=5 os_prio=0 cpu=24150.51ms elapsed=8857.08s tid=0x00007f79d450c800 nid=0x2d447a in Object.wait()  [0x00007f794d4b2000]
   java.lang.Thread.State: TIMED_WAITING (on object monitor)
        at java.lang.Object.wait(java.base@11.0.18/Native Method)
        - waiting on <no object reference available>
        at hudson.remoting.Request.call(Request.java:177)
        - waiting to re-lock in wait() <0x00000007aee98d98> (a hudson.remoting.UserRequest)
        at hudson.remoting.Channel.call(Channel.java:999)
        at hudson.FilePath.act(FilePath.java:1194)
        at hudson.FilePath.list(FilePath.java:2063)
        at hudson.FilePath.listDirectories(FilePath.java:2037)
        at jenkins.branch.WorkspaceLocatorImpl$Collector.onOnline(WorkspaceLocatorImpl.java:612)
        - locked <0x000000060d199a70> (a java.lang.String)
        at hudson.slaves.SlaveComputer.setChannel(SlaveComputer.java:748)

We don't know for sure why EC2s agent doesn't like this:
waiting for EC2 (DevSecOps Agent)

but we do know it is fine on local storage, but not NFS.

What is interesting is this:

Perhaps this could be refactored in order to deal with a large amount of directories on NFS?