Getting an Assertion error where the JIRA plugin is apparently missing its descriptor

Symptoms

When trying to save a job or modify a configuration for the JIRA plugin I am getting the following error:

java.lang.AssertionError: class hudson.plugins.jira.JiraGlobalConfiguration is missing its descriptor
at jenkins.model.Jenkins.getDescriptorOrDie(Jenkins.java:1545)
at hudson.plugins.jira.JiraGlobalConfiguration.get(JiraGlobalConfiguration.java:16)
at hudson.plugins.jira.JiraProjectProperty$DescriptorImpl.doFillSiteNameItems(JiraProjectProperty.java:110)
at java.lang.invoke.MethodHandle.invokeWithArguments(MethodHandle.java:627)
at org.kohsuke.stapler.Function$MethodFunction.invoke(Function.java:396)
at org.kohsuke.stapler.Function$InstanceFunction.invoke(Function.java:408)
at org.kohsuke.stapler.Function.bindAndInvoke(Function.java:212)
at org.kohsuke.stapler.Function.bindAndInvokeAndServeResponse(Function.java:145)
at org.kohsuke.stapler.MetaClass$11.doDispatch(MetaClass.java:535)
at org.kohsuke.stapler.NameBasedDispatcher.dispatch(NameBasedDispatcher.java:58)
at org.kohsuke.stapler.Stapler.tryInvoke(Stapler.java:747)
Caused: javax.servlet.ServletException

Environment

CloudBees CI (CloudBees Core)
CloudBees Jenkins Enterprise - Managed controller (CJE-MM)
Jenkins LTS
JIRA Plugin

Cause

The above error is due to your Jenkins instance being unable to properly read the Global Configuration file for the JIRA plugin

Steps To Fix

CAUTION This will cause you to lose your existing JIRA global configuration

Navigate to your $JENKINS_HOME and rename the file hudson.plugins.jira.JiraGlobalConfiguration.xml to hudson.plugins.jira.JiraGlobalConfiguration.xml.bak. Then you will need to restart the Jenkins instance but will have lost the configuration from the Manage Jenkins> Configure System page. Just replace it again with the previous JIRA details and your instance should work normally again.