I've recently started seeing this warning popping up in my Jenkins system log:

Feb 12, 2016 3:26:43 PM WARNING jenkins.metrics.util.HealthChecksThreadPool dropOldestInQueue

Too many health check executions queued, dropping oldest one. This may mean some health checks are taking too long to execute: jenkins.metrics.util.HealthChecksThreadPool@3cf11acf[Running, pool size = 0, active threads = 0, queued tasks = 0, completed tasks = 503], queue size=1, health checks=[disk-space, plugins, temporary-space, thread-deadlock] (4) [java.util.concurrent.FutureTask@8afd366]

Feb 12, 2016 3:26:43 PM WARNING com.codahale.metrics.health.HealthCheckRegistry runHealthChecks

Error executing health check thread-deadlock
java.util.concurrent.CancellationException
at java.util.concurrent.FutureTask.report(FutureTask.java:121)
at java.util.concurrent.FutureTask.get(FutureTask.java:188)
at com.codahale.metrics.health.HealthCheckRegistry.runHealthChecks(HealthCheckRegistry.java:102)
at jenkins.metrics.api.Metrics$HealthChecker.execute(Metrics.java:592)
at jenkins.metrics.api.Metrics$HealthChecker.access$500(Metrics.java:402)
at jenkins.metrics.api.Metrics$HealthChecker$3.run(Metrics.java:532)
at java.util.concurrent.Executors$RunnableAdapter.call(Executors.java:471)
at java.util.concurrent.FutureTask.run(FutureTask.java:262)
at java.util.concurrent.ThreadPoolExecutor.runWorker(ThreadPoolExecutor.java:1145)
at java.util.concurrent.ThreadPoolExecutor$Worker.run(ThreadPoolExecutor.java:615)
at java.lang.Thread.run(Thread.java:745)

I only noticed it today but I look at the logs every couple of days at least, and I haven't seen it until now. A Google search doesn't return any other instances of it appearing, so beyond a quick glance at the source code I can't say for sure what's causing it. As a one time thing I'd write it off but I'm seeing it repeated every couple of minutes following my last reboot. Should I be concerned about this?