I added an 'Execute Scripts on Matrix' post build step.

This exception also occurs with 'Execute Scripts' post build step.

I added a groovy script file with a simple println statement and ran the job.
[PostBuildScript] - Problem occurred: java.lang.IllegalStateException: maybe need to rebuild plugin?
at org.jenkinsci.plugins.scriptsecurity.scripts.ScriptApproval.get(ScriptApproval.java:99)
at org.jenkinsci.plugins.scriptsecurity.sandbox.groovy.SecureGroovyScript.configuring(SecureGroovyScript.java:126)
at org.jenkinsci.plugins.scriptsecurity.sandbox.groovy.SecureGroovyScript.configuringWithNonKeyItem(SecureGroovyScript.java:150)
at org.jenkinsci.plugins.postbuildscript.service.GroovyScriptExecutor.call(GroovyScriptExecutor.java:54)
at org.jenkinsci.plugins.postbuildscript.service.GroovyScriptExecutor.call(GroovyScriptExecutor.java:17)
at hudson.remoting.UserRequest.perform(UserRequest.java:207)
at hudson.remoting.UserRequest.perform(UserRequest.java:53)
at hudson.remoting.Request$2.run(Request.java:358)
at hudson.remoting.InterceptingExecutorService$1.call(InterceptingExecutorService.java:72)
at java.util.concurrent.FutureTask.run(FutureTask.java:266)
at java.util.concurrent.ThreadPoolExecutor.runWorker(ThreadPoolExecutor.java:1142)
at java.util.concurrent.ThreadPoolExecutor$Worker.run(ThreadPoolExecutor.java:617)
at java.lang.Thread.run(Thread.java:745)
Suppressed: hudson.remoting.Channel$CallSiteStackTrace: Remote call to bldsvr03
at hudson.remoting.Channel.attachCallSiteStackTrace(Channel.java:1693)
at hudson.remoting.UserResponse.retrieve(UserRequest.java:310)
at hudson.remoting.Channel.call(Channel.java:908)
at hudson.FilePath.act(FilePath.java:1081)
at org.jenkinsci.plugins.postbuildscript.service.GroovyScriptPreparer.evaluateScript(GroovyScriptPreparer.java:54)
at org.jenkinsci.plugins.postbuildscript.service.GroovyScriptPreparer.evaluateScript(GroovyScriptPreparer.java:40)
at org.jenkinsci.plugins.postbuildscript.processor.Processor.processGroovyScripts(Processor.java:160)
at org.jenkinsci.plugins.postbuildscript.processor.Processor.processScripts(Processor.java:97)
at org.jenkinsci.plugins.postbuildscript.processor.Processor.process(Processor.java:83)
at org.jenkinsci.plugins.postbuildscript.ConfigurableMatrixAggregator.endBuild(ConfigurableMatrixAggregator.java:35)
at hudson.matrix.MatrixBuild$MatrixBuildExecution.post2(MatrixBuild.java:424)
at hudson.model.AbstractBuild$AbstractBuildExecution.post(AbstractBuild.java:635)
at hudson.model.Run.execute(Run.java:1749)
at hudson.matrix.MatrixBuild.run(MatrixBuild.java:314)
at hudson.model.ResourceController.execute(ResourceController.java:97)
at hudson.model.Executor.run(Executor.java:429)