java.lang.StringIndexOutOfBoundsException: String index out of range: -1
at java.lang.String.substring(Unknown Source)
at java.lang.String.substring(Unknown Source)
at hudson.plugins.lockedfilesreport.FindFilesInUseWithHandle.parseOutput(FindFilesInUseWithHandle.java:38)
at hudson.plugins.lockedfilesreport.LockedFilesReporter$GetUsedFiles.invoke(LockedFilesReporter.java:115)
at hudson.plugins.lockedfilesreport.LockedFilesReporter$GetUsedFiles.invoke(LockedFilesReporter.java:98)
at hudson.FilePath$FileCallableWrapper.call(FilePath.java:1899)
at hudson.remoting.UserRequest.perform(UserRequest.java:114)
at hudson.remoting.UserRequest.perform(UserRequest.java:48)
at hudson.remoting.Request$2.run(Request.java:270)
at java.util.concurrent.Executors$RunnableAdapter.call(Unknown Source)
at java.util.concurrent.FutureTask$Sync.innerRun(Unknown Source)
at java.util.concurrent.FutureTask.run(Unknown Source)
at java.util.concurrent.ThreadPoolExecutor$Worker.runTask(Unknown Source)
at java.util.concurrent.ThreadPoolExecutor$Worker.run(Unknown Source)
at hudson.remoting.Engine$1$1.run(Engine.java:58)
at java.lang.Thread.run(Unknown Source)

This has only happened once, but it is happening consistently on one job.